Repository navigation
Generate sourcemaps for production build artifacts - #26446
Merged
Merged
Conversation
markerikson
force-pushed
the
feature/build-prod-sourcemaps
branch
from
March 21, 2023 19:28
f389e3d to
72029f3
Compare
markerikson
force-pushed
the
feature/build-prod-sourcemaps
branch
3 times, most recently
from
March 21, 2023 22:32
c55dbf9 to
ca37e8c
Compare
Contributor
Author
|
And this PR is now green! It still needs an actual review, and also to rebased after the Rollup v3 PR is merged, but the sourcemaps work and CI is passing. |
Merged
markerikson
force-pushed
the
feature/build-prod-sourcemaps
branch
from
March 24, 2023 18:25
ca37e8c to
fc846c2
Compare
Contributor
Author
Contributor
|
Note that this PR will supercede and invalidate past work on this such as: |
Closed
Contributor
|
Will this PR also help with sourcemaps in debug builds? In the past, debugging into React source code with the VS Code debugger has been a challenge, I assume because sourcemaps were not aligned with the actual sources. |
Contributor
Author
|
@justingrant : no , I'm not trying to generate sourcemaps for dev build artifacts, because those should already be readable. Do you have an example where debugging a React dev build isn't working well? |
Contributor
|
@markerikson - my experience is pretty dated from a few years ago, and was largely focused on create-react-app which handled sourcemap creation in its webpack config. Things might have improved since then. But I do remember that debugging into debug React builds seldom/never aligned with the source. If you believe it's working now, then I'm inclined to trust your judgment and assume that the problems I was seeing were caused by CRA not React's debug sourcemaps. @jasonwilliams was also looking into this so he may have more info. |
Contributor
Author
|
@gaearon you mentioned on Twitter that "the license stuff is complicated". Any specific concerns there, or other feedback on the PR? |
Contributor
|
Yes. I don't fully understand what's going on there. One option is that I need to dive into this. Another is that I can pose a constraint from my perspective. This constraint is: can we reduce any manual string manipulation in this PR? Ideally there would be none. What would the approach look like if we did not have any string manipulation code? If it's due to license headers, can we inject them at a different stage (e.g. earlier), or inject them in a way that automatically adjusts the sourcemaps? What is the sequence of problems that make this code necessary? |
Contributor
Author
|
There's a couple pieces here. Rollup's own sourcemap handling normally produces a sourcemap where the "original" code is "the individual original source files", such as Because of that, what we we really want is to have a sourcemap where the "original" code is actually "the bundle contents right before Closure minified it" - in other words, the code that actually executed in the user's app. In order to make this happen, I skipped Rollup's sourcemap handling, and had Closure write a sourcemap for its minification step to disk. That contains 95% of the actual sourcemap content that we need. However, there's one more step in the Rollup pipeline after Closure. Because of that, the sourcemap from the Closure step is no longer accurate. If a particular mapping instruction pointed to a specific line segment in the output, the addition of the license text + wrapper before that in the final output throws off all the mappings. In order to align things correctly, we have to generate a sourcemap for the "possibly minified bundle -> bundle with license wrapper" step, and merge that with the "pre-minified bundle -> post-minified bundle" step. The best option I could come up with for doing that was to take the output of the license step, split it using the code to get the pieces that were added before and after, and re-run that step with a sourcemap-aware tool (the same It's maybe possible that we could move the license step before the Closure step, but I suspect that Closure would immediately strip off the license headers because those are comments. Don't know if there's somehow a Closure option that would allow us to preserve the headers. Also not sure what effect that would have on the rest of the module wrapping code that I also played with using With this approach, the bulk of the sourcemap work is in the one custom Rollup plugin there after the license plugin, and almost all the code changes are inside |
Contributor
@markerikson @gaearon @jasonwilliams For historical purposes, this was also an approach I explored back in July 2022 when I was looking into fixing the things required to get sourcemap support added. From a quick search, this seems to be (at least one of the) places where I was looking at the license wrapper code, and proposed using
It includes a bit of a code exploration, some exploration of related libraries, and some proposals/diffs of how it could be used within the existing wrapper code in a 'minimally different'/low touch way, that should be simple to maintain, etc. |
0xdevalias
reviewed
Mar 29, 2023
0xdevalias
reviewed
Mar 29, 2023
Contributor
Author
|
Huh. I just tried reordering the Rollup plugins so that the license step does go before Closure and it skips the string manipulation step... and I think it's working the same way? I did a very brief search last night and think I found an indication that Closure might preserve comments with I need to do some more investigation here, but this seems promising at first glance. |
markerikson
force-pushed
the
feature/build-prod-sourcemaps
branch
from
March 29, 2023 20:00
fc846c2 to
e485811
Compare
Contributor
Author
|
Adding the license + wrappers before the Closure step seems to work. I did have to add an extra That removes the need for the string manipulation and the extra sourcemap merging step. The sourcemaps themselves still appear to be fully accurate. Some of the RN dev bundles have increased in size, but that appears to be due to them getting formatted by Prettier more so than they were previously (function call args getting split across multiple lines, etc). No actual content changes that I can see. |
markerikson
force-pushed
the
feature/build-prod-sourcemaps
branch
from
March 29, 2023 20:10
e485811 to
b1c8802
Compare
Contributor
Author
|
@gaearon I think this looks pretty good! Please look it over when you get a chance and let me know if you have further feedback! |
gaearon
reviewed
Mar 31, 2023
|
|
||
| // Any other packages that should specifically _not_ have sourcemaps | ||
| const sourcemapPackageExcludes = [ | ||
| // Having `//#sourceMappingUrl` in this file breaks `ReactDevToolsHooksIntegration-test.js`, |
Contributor
There was a problem hiding this comment.
Why? Can we fix the test to be more resilient instead?
Contributor
Author
There was a problem hiding this comment.
Not sure. It took me close to an hour just to figure out that having a sourcemap URL added to that bundle file was even the reason why that test was failing, and I have no idea why that was the case. Seemed to be something about imports or source parsing, maybe.
Per the comment, that file really doesn't need to have sourcemaps anyway, so it's reasonable to exclude it.
Contributor
There was a problem hiding this comment.
I appreciate the time spent on this, but we generally try to understand each problem exhaustively before attempting a fix. In this case, it's important to understand why the test fails. Especially since the test has something to do with DevTools integration (which relies on parsing stacks), and might be flagging a real problem.
Even if it's not a real problem, imagine someone adding another package with similar logic, and then being confused why this logic doesn't fail tests when it's inside react-debug-tools, but does elsewhere. Then they would have to spend an hour only to find that react-debug-tools is somehow exceptional.
We do need to get to the bottom of the real cause.
Contributor
Author
There was a problem hiding this comment.
Okay, I'll dig into this further and see if I can understand what's going on.
Contributor
There was a problem hiding this comment.
isStateEditable is calculated here so you might want to check if the primitive value is affected by the presence of sourcemaps. Maybe something gets borked in the stack parsing logic.
Contributor
Author
There was a problem hiding this comment.
Did some further poking at this. I think this is due to the react-debug-tools logic combined with the actual test setup in the first place.
The stack trace string, prior to being parsed, is:
Error:
at Object.apply (/home/acemarke/projects/react/scripts/jest/setupTests.js:219:29)
at Proxy.Error (/home/acemarke/projects/react/build/oss-stable/react-debug-tools/cjs/react-debug-tools.production.min.js:122:21)
at Object.useReducer (/home/acemarke/projects/react/build/oss-stable/react/cjs/react.production.min.js:959:21)
at MyComponent (/home/acemarke/projects/react/packages/react-debug-tools/src/__tests__/ReactDevToolsHooksIntegration-test.js:101:13)
at renderFunction (/home/acemarke/projects/react/build/oss-stable/react-debug-tools/cjs/react-debug-tools.production.min.js:652:5)
at Object.inspectHooks [as inspectHooksOfFiber] (/home/acemarke/projects/react/build/oss-stable/react-debug-tools/cjs/react-debug-tools.production.min.js:763:12)
at Object.<anonymous> (/home/acemarke/projects/react/packages/react-debug-tools/src/__tests__/ReactDevToolsHooksIntegration-test.js:118:32)
Note that Proxy.Error is already in the stack trace string.
react-debug-tools.production.min.js:122 is:
useInsertionEffect: function(a) {
C();
x.push({
primitive: "InsertionEffect",
stackError: Error(),
value: a
})
},Note the line stackError: Error(), and .stackError is what's getting passed to the error-stack-parser library.
If you look at scripts/jest/setupTests.js, it has this logic that overwrites global.Error with a proxy:
const ErrorProxy = new Proxy(OriginalError, {
apply(target, thisArg, argumentsList) {
const error = Reflect.apply(target, thisArg, argumentsList);
error.message = decodeErrorMessage(error.message);
return proxyErrorInstance(error);
},
construct(target, argumentsList, newTarget) {
const error = Reflect.construct(target, argumentsList, newTarget);
error.message = decodeErrorMessage(error.message);
return proxyErrorInstance(error);
},
get(target, key, receiver) {
if (key === 'captureStackTrace') {
return captureStackTrace;
}
return Reflect.get(target, key, receiver);
},
});
ErrorProxy.OriginalError = OriginalError;
global.Error = ErrorProxy;So, I think the inclusion of the sourcemap for react-debug-tools.production.min.js is causing Node to alter the stack trace related to that global.Error = ErrorProxy, which ends up breaking the parsing later.
Contributor
There was a problem hiding this comment.
Sorry, I still don't quite understand. Where is the mistake? Which part is wrong here?
Contributor
Author
There was a problem hiding this comment.
@gaearon : there is no "mistake" per se.
The test setup code works as intended. The error stack parsing code works as intended.
But per my last comment, having a sourcemap for react-debug-tools.production.min.js causes Node to have different stack trace contents for the thrown error, which then causes the hook name parsing logic to fail to match what it expected to see.
We know this test worked fine when there was no sourcemap. It's an internal package, and there's no reason to have a sourcemap for this bundle.
So, we should skip it and keep the behavior the same as it was.
Collaborator
There was a problem hiding this comment.
We know this test worked fine when there was no sourcemap. It's an internal package, and there's no reason to have a sourcemap for this bundle.
Can confirm that this package is a part of React DevTools' backend, but for historical reasons (which I don't know) it is present as a separate package in this monorepo.
Contributor
Author
There was a problem hiding this comment.
Yeah, I did just actually happen to talk to Brian today about the fact that gets used as part of the RDT backend to parse hook names.
That said, while it's technically published ( https://www.npmjs.com/package/react-debug-tools ) , it doesn't look like it's even been published at all since the first release 5 years ago, and it seems like the only references are inside of the RDT internals. So, still no reason that I can see to justify having a sourcemap generated for that package, especially given the test situation.
markerikson
force-pushed
the
feature/build-prod-sourcemaps
branch
from
March 31, 2023 14:58
b1c8802 to
7d71363
Compare
markerikson
force-pushed
the
feature/build-prod-sourcemaps
branch
from
April 12, 2023 15:18
7d71363 to
5daa4ba
Compare
Contributor
Author
|
AWESOME! Thank you so much for helping push this through! Please let me know if there's any last-minute tweaks needed and I can get those done today. |
hoxyq
approved these changes
Nov 7, 2023
Contributor
|
🥳 |
Collaborator
|
Thanks again for working on this @markerikson! |
Contributor
Author
|
Awesome! And thank you for helping push this across the finish line! |
github-actions Bot
pushed a commit
that referenced
this pull request
Nov 7, 2023
<!-- Thanks for submitting a pull request! We appreciate you spending the time to work on these changes. Please provide enough information so that others can review your pull request. The three fields below are mandatory. Before submitting a pull request, please make sure the following is done: 1. Fork [the repository](https://github.com/facebook/react) and create your branch from `main`. 2. Run `yarn` in the repository root. 3. If you've fixed a bug or added code that should be tested, add tests! 4. Ensure the test suite passes (`yarn test`). Tip: `yarn test --watch TestName` is helpful in development. 5. Run `yarn test --prod` to test in the production environment. It supports the same options as `yarn test`. 6. If you need a debugger, run `yarn test --debug --watch TestName`, open `chrome://inspect`, and press "Inspect". 7. Format your code with [prettier](https://github.com/prettier/prettier) (`yarn prettier`). 8. Make sure your code lints (`yarn lint`). Tip: `yarn linc` to only check changed files. 9. Run the [Flow](https://flowtype.org/) type checks (`yarn flow`). 10. If you haven't already, complete the CLA. Learn more about contributing: https://reactjs.org/docs/how-to-contribute.html --> ## Summary This PR updates the Rollup build pipeline to generate sourcemaps for production build artifacts like `react-dom.production.min.js`. It requires the Rollup v3 changes that were just merged in #26442 . Sourcemaps are currently _only_ generated for build artifacts that are _truly_ "production" - no sourcemaps will be generated for development, profiling, UMD, or `shouldStayReadable` artifacts. The generated sourcemaps contain the bundled source contents right before that chunk was minified by Closure, and _not_ the original source files like `react-reconciler/src/*`. This better reflects the actual code that is running as part of the bundle, with all the feature flags and transformations that were applied to the source files to generate that bundle. The sourcemaps _do_ still show comments and original function names, thus improving debuggability for production usage. Fixes #20186 . <!-- Explain the **motivation** for making this change. What existing problem does the pull request solve? --> This allows React users to actually debug a readable version of the React bundle in production scenarios. It also allows other tools like [Replay](https://replay.io) to do a better job inspecting the React source when stepping through. ## How did you test this change? - Generated numerous sourcemaps with various combinations of the React bundle selections - Viewed those sourcemaps in https://evanw.github.io/source-map-visualization/ and confirmed via the visualization that the generated mappings appear to be correct I've attached a set of production files + their sourcemaps here: [react-sourcemap-examples.zip](https://github.com/facebook/react/files/11023466/react-sourcemap-examples.zip) You can drag JS+sourcemap file pairs into https://evanw.github.io/source-map-visualization/ for viewing. Examples: - `react.production.min.js`:  - `react-dom.production.min.js`:  - `use-sync-external-store/with-selector.production.min.js`:  <!-- Demonstrate the code is solid. Example: The exact commands you ran and their output, screenshots / videos if the pull request changes the user interface. How exactly did you verify that your PR solves the issue you wanted to solve? If you leave this empty, your PR will very likely be closed. --> DiffTrain build for [2c8a139](2c8a139)
|
wahooo 🥳 |
gnoff
added a commit
to gnoff/next.js
that referenced
this pull request
Nov 8, 2023
kodiakhq Bot
pushed a commit
to vercel/next.js
that referenced
this pull request
Nov 8, 2023
Updated React from 2983249dd to 7508dcd5c. - react/react#27672 - react/react#27132 - react/react#27646 - react/react#26446
1 task done
EdisonVan
pushed a commit
to EdisonVan/react
that referenced
this pull request
Apr 15, 2024
<!-- Thanks for submitting a pull request! We appreciate you spending the time to work on these changes. Please provide enough information so that others can review your pull request. The three fields below are mandatory. Before submitting a pull request, please make sure the following is done: 1. Fork [the repository](https://github.com/facebook/react) and create your branch from `main`. 2. Run `yarn` in the repository root. 3. If you've fixed a bug or added code that should be tested, add tests! 4. Ensure the test suite passes (`yarn test`). Tip: `yarn test --watch TestName` is helpful in development. 5. Run `yarn test --prod` to test in the production environment. It supports the same options as `yarn test`. 6. If you need a debugger, run `yarn test --debug --watch TestName`, open `chrome://inspect`, and press "Inspect". 7. Format your code with [prettier](https://github.com/prettier/prettier) (`yarn prettier`). 8. Make sure your code lints (`yarn lint`). Tip: `yarn linc` to only check changed files. 9. Run the [Flow](https://flowtype.org/) type checks (`yarn flow`). 10. If you haven't already, complete the CLA. Learn more about contributing: https://reactjs.org/docs/how-to-contribute.html --> ## Summary This PR updates the Rollup build pipeline to generate sourcemaps for production build artifacts like `react-dom.production.min.js`. It requires the Rollup v3 changes that were just merged in react#26442 . Sourcemaps are currently _only_ generated for build artifacts that are _truly_ "production" - no sourcemaps will be generated for development, profiling, UMD, or `shouldStayReadable` artifacts. The generated sourcemaps contain the bundled source contents right before that chunk was minified by Closure, and _not_ the original source files like `react-reconciler/src/*`. This better reflects the actual code that is running as part of the bundle, with all the feature flags and transformations that were applied to the source files to generate that bundle. The sourcemaps _do_ still show comments and original function names, thus improving debuggability for production usage. Fixes react#20186 . <!-- Explain the **motivation** for making this change. What existing problem does the pull request solve? --> This allows React users to actually debug a readable version of the React bundle in production scenarios. It also allows other tools like [Replay](https://replay.io) to do a better job inspecting the React source when stepping through. ## How did you test this change? - Generated numerous sourcemaps with various combinations of the React bundle selections - Viewed those sourcemaps in https://evanw.github.io/source-map-visualization/ and confirmed via the visualization that the generated mappings appear to be correct I've attached a set of production files + their sourcemaps here: [react-sourcemap-examples.zip](https://github.com/facebook/react/files/11023466/react-sourcemap-examples.zip) You can drag JS+sourcemap file pairs into https://evanw.github.io/source-map-visualization/ for viewing. Examples: - `react.production.min.js`:  - `react-dom.production.min.js`:  - `use-sync-external-store/with-selector.production.min.js`:  <!-- Demonstrate the code is solid. Example: The exact commands you ran and their output, screenshots / videos if the pull request changes the user interface. How exactly did you verify that your PR solves the issue you wanted to solve? If you leave this empty, your PR will very likely be closed. -->
bigfootjon
pushed a commit
that referenced
this pull request
Apr 18, 2024
<!-- Thanks for submitting a pull request! We appreciate you spending the time to work on these changes. Please provide enough information so that others can review your pull request. The three fields below are mandatory. Before submitting a pull request, please make sure the following is done: 1. Fork [the repository](https://github.com/facebook/react) and create your branch from `main`. 2. Run `yarn` in the repository root. 3. If you've fixed a bug or added code that should be tested, add tests! 4. Ensure the test suite passes (`yarn test`). Tip: `yarn test --watch TestName` is helpful in development. 5. Run `yarn test --prod` to test in the production environment. It supports the same options as `yarn test`. 6. If you need a debugger, run `yarn test --debug --watch TestName`, open `chrome://inspect`, and press "Inspect". 7. Format your code with [prettier](https://github.com/prettier/prettier) (`yarn prettier`). 8. Make sure your code lints (`yarn lint`). Tip: `yarn linc` to only check changed files. 9. Run the [Flow](https://flowtype.org/) type checks (`yarn flow`). 10. If you haven't already, complete the CLA. Learn more about contributing: https://reactjs.org/docs/how-to-contribute.html --> ## Summary This PR updates the Rollup build pipeline to generate sourcemaps for production build artifacts like `react-dom.production.min.js`. It requires the Rollup v3 changes that were just merged in #26442 . Sourcemaps are currently _only_ generated for build artifacts that are _truly_ "production" - no sourcemaps will be generated for development, profiling, UMD, or `shouldStayReadable` artifacts. The generated sourcemaps contain the bundled source contents right before that chunk was minified by Closure, and _not_ the original source files like `react-reconciler/src/*`. This better reflects the actual code that is running as part of the bundle, with all the feature flags and transformations that were applied to the source files to generate that bundle. The sourcemaps _do_ still show comments and original function names, thus improving debuggability for production usage. Fixes #20186 . <!-- Explain the **motivation** for making this change. What existing problem does the pull request solve? --> This allows React users to actually debug a readable version of the React bundle in production scenarios. It also allows other tools like [Replay](https://replay.io) to do a better job inspecting the React source when stepping through. ## How did you test this change? - Generated numerous sourcemaps with various combinations of the React bundle selections - Viewed those sourcemaps in https://evanw.github.io/source-map-visualization/ and confirmed via the visualization that the generated mappings appear to be correct I've attached a set of production files + their sourcemaps here: [react-sourcemap-examples.zip](https://github.com/facebook/react/files/11023466/react-sourcemap-examples.zip) You can drag JS+sourcemap file pairs into https://evanw.github.io/source-map-visualization/ for viewing. Examples: - `react.production.min.js`:  - `react-dom.production.min.js`:  - `use-sync-external-store/with-selector.production.min.js`:  <!-- Demonstrate the code is solid. Example: The exact commands you ran and their output, screenshots / videos if the pull request changes the user interface. How exactly did you verify that your PR solves the issue you wanted to solve? If you leave this empty, your PR will very likely be closed. --> DiffTrain build for commit 2c8a139.
acdlite
added a commit
that referenced
this pull request
Apr 19, 2024
In #26446 we started publishing non-minified versions of our production build artifacts, along with source maps, for easier debugging of React when running in production mode. The way it's currently set up is that these builds are generated *before* Closure compiler has run. Which means it's missing many of the optimizations that are in the final build, like dead code elimination. This PR changes the build process to run Closure on the non-minified production builds, too, by moving the sourcemap generation to later in the pipeline. The non-minified builds will still preserve the original symbol names, and we'll use Prettier to add back whitespace. This is the exact same approach we've been using for years to generate production builds for Meta. The idea is that the only difference between the minified and non- minified builds is whitespace and symbol mangling. The semantic structure of the program should be identical. To implement this, I disabled symbol mangling when running Closure compiler. Then, in a later step, the symbols are mangled by Terser. This is when the source maps are generated.
github-actions Bot
pushed a commit
that referenced
this pull request
Apr 19, 2024
In #26446 we started publishing non-minified versions of our production build artifacts, along with source maps, for easier debugging of React when running in production mode. The way it's currently set up is that these builds are generated *before* Closure compiler has run. Which means it's missing many of the optimizations that are in the final build, like dead code elimination. This PR changes the build process to run Closure on the non-minified production builds, too, by moving the sourcemap generation to later in the pipeline. The non-minified builds will still preserve the original symbol names, and we'll use Prettier to add back whitespace. This is the exact same approach we've been using for years to generate production builds for Meta. The idea is that the only difference between the minified and non- minified builds is whitespace and symbol mangling. The semantic structure of the program should be identical. To implement this, I disabled symbol mangling when running Closure compiler. Then, in a later step, the symbols are mangled by Terser. This is when the source maps are generated. DiffTrain build for commit 0e0b693.
github-actions Bot
pushed a commit
that referenced
this pull request
Apr 19, 2024
In #26446 we started publishing non-minified versions of our production build artifacts, along with source maps, for easier debugging of React when running in production mode. The way it's currently set up is that these builds are generated *before* Closure compiler has run. Which means it's missing many of the optimizations that are in the final build, like dead code elimination. This PR changes the build process to run Closure on the non-minified production builds, too, by moving the sourcemap generation to later in the pipeline. The non-minified builds will still preserve the original symbol names, and we'll use Prettier to add back whitespace. This is the exact same approach we've been using for years to generate production builds for Meta. The idea is that the only difference between the minified and non- minified builds is whitespace and symbol mangling. The semantic structure of the program should be identical. To implement this, I disabled symbol mangling when running Closure compiler. Then, in a later step, the symbols are mangled by Terser. This is when the source maps are generated. DiffTrain build for [0e0b693](0e0b693)
bigfootjon
pushed a commit
that referenced
this pull request
Apr 25, 2024
In #26446 we started publishing non-minified versions of our production build artifacts, along with source maps, for easier debugging of React when running in production mode. The way it's currently set up is that these builds are generated *before* Closure compiler has run. Which means it's missing many of the optimizations that are in the final build, like dead code elimination. This PR changes the build process to run Closure on the non-minified production builds, too, by moving the sourcemap generation to later in the pipeline. The non-minified builds will still preserve the original symbol names, and we'll use Prettier to add back whitespace. This is the exact same approach we've been using for years to generate production builds for Meta. The idea is that the only difference between the minified and non- minified builds is whitespace and symbol mangling. The semantic structure of the program should be identical. To implement this, I disabled symbol mangling when running Closure compiler. Then, in a later step, the symbols are mangled by Terser. This is when the source maps are generated. DiffTrain build for commit 0e0b693.
henriettelienrebnor
pushed a commit
to equinor/Dexpi2Imf
that referenced
this pull request
Apr 23, 2025
<h3>Snyk has created this PR to upgrade react from 19.0.0 to
19.1.0.</h3>
:information_source: Keep your dependencies up-to-date. This makes it
easier to fix existing vulnerabilities and to more quickly identify and
fix newly disclosed vulnerabilities when they affect your project.
<hr/>
- The recommended version is **78 versions** ahead of your current
version.
- The recommended version was released **22 days ago**.
<details>
<summary><b>Release notes</b></summary>
<br/>
<details>
<summary>Package name: <b>react</b></summary>
<ul>
<li>
<b>19.1.0</b> - <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Freleases%2Ftag%2Fv19.1.0">2025-03-28</a></br><h3>Owner
Stack</h3>
<p>An Owner Stack is a string representing the components that are
directly responsible for rendering a particular component. You can log
Owner Stacks when debugging or use Owner Stacks to enhance error
overlays or other development tools. Owner Stacks are only available in
development builds. Component Stacks in production are unchanged.</p>
<ul>
<li>An Owner Stack is a development-only stack trace that helps identify
which components are responsible for rendering a particular component.
An Owner Stack is distinct from a Component Stacks, which shows the
hierarchy of components leading to an error.</li>
<li>The <a href="/api/browser/proxy?url=https%3A%2F%2Freact.dev%2Freference%2Freact%2FcaptureOwnerStack"
rel="nofollow">captureOwnerStack API</a> is only available in
development mode and returns a Owner Stack, if available. The API can be
used to enhance error overlays or log component relationships when
debugging. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29923"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29923/hovercard">#29923</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32353"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32353/hovercard">#32353</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F30306"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/30306/hovercard">#30306</a>,<br>
<a href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32538"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32538/hovercard">#32538</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32529"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32529/hovercard">#32529</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32538"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32538/hovercard">#32538</a></li>
</ul>
<h3>React</h3>
<ul>
<li>Enhanced support for Suspense boundaries to be used anywhere,
including the client, server, and during hydration. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32069"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32069/hovercard">#32069</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32163"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32163/hovercard">#32163</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32224"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32224/hovercard">#32224</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32252"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32252/hovercard">#32252</a></li>
<li>Reduced unnecessary client rendering through improved hydration
scheduling <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31751"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31751/hovercard">#31751</a></li>
<li>Increased priority of client rendered Suspense boundaries <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31776"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31776/hovercard">#31776</a></li>
<li>Fixed frozen fallback states by rendering unfinished Suspense
boundaries on the client. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31620"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31620/hovercard">#31620</a></li>
<li>Reduced garbage collection pressure by improving Suspense boundary
retries. <a href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31667"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31667/hovercard">#31667</a></li>
<li>Fixed erroneous “Waiting for Paint” log when the passive effect
phase was not delayed <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31526"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31526/hovercard">#31526</a></li>
<li>Fixed a regression causing key warnings for flattened positional
children in development mode. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32117"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32117/hovercard">#32117</a></li>
<li>Updated <code>useId</code> to use valid CSS selectors, changing
format from <code>:r123:</code> to <code>«r123»</code>. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32001"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32001/hovercard">#32001</a></li>
<li>Added a dev-only warning for null/undefined created in useEffect,
useInsertionEffect, and useLayoutEffect. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32355"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32355/hovercard">#32355</a></li>
<li>Fixed a bug where dev-only methods were exported in production
builds. React.act is no longer available in production builds. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32200"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32200/hovercard">#32200</a></li>
<li>Improved consistency across prod and dev to improve compatibility
with Google Closure Complier and bindings <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31808"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31808/hovercard">#31808</a></li>
<li>Improve passive effect scheduling for consistent task yielding. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31785"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31785/hovercard">#31785</a></li>
<li>Fixed asserts in React Native when
passChildrenWhenCloningPersistedNodes is enabled for OffscreenComponent
rendering. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32528"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32528/hovercard">#32528</a></li>
<li>Fixed component name resolution for Portal <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32640"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32640/hovercard">#32640</a></li>
<li>Added support for beforetoggle and toggle events on the dialog
element. <a class="issue-link js-issue-link" data-error-text="Failed to
load title" data-id="2882132160" data-permission-text="Title is private"
data-url="https://github.com/facebook/react/issues/32479"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32479/hovercard"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32479">#32479</a>
<a href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32479"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32479/hovercard">#32479</a></li>
</ul>
<h3>React DOM</h3>
<ul>
<li>Fixed double warning when the <code>href</code> attribute is an
empty string <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31783"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31783/hovercard">#31783</a></li>
<li>Fixed an edge case where <code>getHoistableRoot()</code> didn’t work
properly when the container was a Document <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32321"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32321/hovercard">#32321</a></li>
<li>Removed support for using HTML comments (e.g. <code><!--
--></code>) as a DOM container. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32250"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32250/hovercard">#32250</a></li>
<li>Added support for <code><script></code> and
<code><template></code> tags to be nested within
<code><select></code> tags. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31837"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31837/hovercard">#31837</a></li>
<li>Fixed responsive images to be preloaded as HTML instead of headers
<a href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32445"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32445/hovercard">#32445</a></li>
</ul>
<h3>use-sync-external-store</h3>
<ul>
<li>Added <code>exports</code> field to <code>package.json</code> for
<code>use-sync-external-store</code> to support various entrypoints. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25231"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25231/hovercard">#25231</a></li>
</ul>
<h3>React Server Components</h3>
<ul>
<li>Added <code>unstable_prerender</code>, a new experimental API for
prerendering React Server Components on the server <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31724"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31724/hovercard">#31724</a></li>
<li>Fixed an issue where streams would hang when receiving new chunks
after a global error <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31840"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31840/hovercard">#31840</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31851"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31851/hovercard">#31851</a></li>
<li>Fixed an issue where pending chunks were counted twice. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31833"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31833/hovercard">#31833</a></li>
<li>Added support for streaming in edge environments <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31852"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31852/hovercard">#31852</a></li>
<li>Added support for sending custom error names from a server so that
they are available in the client for console replaying. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32116"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32116/hovercard">#32116</a></li>
<li>Updated the server component wire format to remove IDs for hints and
console.log because they have no return value <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31671"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31671/hovercard">#31671</a></li>
<li>Exposed <code>registerServerReference</code> in client builds to
handle server references in different environments. <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32534"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32534/hovercard">#32534</a></li>
<li>Added react-server-dom-parcel package which integrates Server
Components with the <a href="/api/browser/proxy?url=https%3A%2F%2Fparceljs.org%2F"
rel="nofollow">Parcel bundler</a> <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31725"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31725/hovercard">#31725</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32132"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32132/hovercard">#32132</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31799"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31799/hovercard">#31799</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F32294"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/32294/hovercard">#32294</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31741"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31741/hovercard">#31741</a></li>
</ul>
</li>
<li>
<b>19.1.0-canary-ff628334-20250205</b> - 2025-02-06
</li>
<li>
<b>19.1.0-canary-fcb4e0f1-20250219</b> - 2025-02-20
</li>
<li>
<b>19.1.0-canary-fc8a898d-20241226</b> - 2024-12-27
</li>
<li>
<b>19.1.0-canary-fbcda19a-20250317</b> - 2025-03-17
</li>
<li>
<b>19.1.0-canary-f9d78089-20250306</b> - 2025-03-07
</li>
<li>
<b>19.1.0-canary-f83903bf-20250212</b> - 2025-02-12
</li>
<li>
<b>19.1.0-canary-f457d0b4-20250313</b> - 2025-03-13
</li>
<li>
<b>19.1.0-canary-f0edf41e-20250115</b> - 2025-01-14
</li>
<li>
<b>19.1.0-canary-ef979d47-20241218</b> - 2024-12-18
</li>
<li>
<b>19.1.0-canary-ef4bc8b4-20250328</b> - 2025-03-28
</li>
<li>
<b>19.1.0-canary-ebc22ef7-20250225</b> - 2025-02-26
</li>
<li>
<b>19.1.0-canary-e670e72f-20250214</b> - 2025-02-14
</li>
<li>
<b>19.1.0-canary-e1e74071-20250321</b> - 2025-03-21
</li>
<li>
<b>19.1.0-canary-e06c72fc-20241215</b> - 2024-12-16
</li>
<li>
<b>19.1.0-canary-e03ac20f-20250305</b> - 2025-03-05
</li>
<li>
<b>19.1.0-canary-de82912e-20241220</b> - 2024-12-20
</li>
<li>
<b>19.1.0-canary-de1eaa26-20250124</b> - 2025-01-24
</li>
<li>
<b>19.1.0-canary-db7dfe05-20250319</b> - 2025-03-19
</li>
<li>
<b>19.1.0-canary-d85cf3e5-20250205</b> - 2025-02-05
</li>
<li>
<b>19.1.0-canary-d55cc79b-20250228</b> - 2025-02-28
</li>
<li>
<b>19.1.0-canary-d46b04a2-20250117</b> - 2025-01-17
</li>
<li>
<b>19.1.0-canary-d4287258-20241217</b> - 2024-12-17
</li>
<li>
<b>19.1.0-canary-d331ba04-20250307</b> - 2025-03-10
</li>
<li>
<b>19.1.0-canary-cd90a4d8-20250210</b> - 2025-02-11
</li>
<li>
<b>19.1.0-canary-cbbe8666-20250213</b> - 2025-02-13
</li>
<li>
<b>19.1.0-canary-cabd8a0e-20250113</b> - 2025-01-13
</li>
<li>
<b>19.1.0-canary-c69a5fc5-20250318</b> - 2025-03-18
</li>
<li>
<b>19.1.0-canary-c492f975-20250128</b> - 2025-01-29
</li>
<li>
<b>19.1.0-canary-c01b8058-20241229</b> - 2024-12-30
</li>
<li>
<b>19.1.0-canary-bb9a24d9-20250130</b> - 2025-01-30
</li>
<li>
<b>19.1.0-canary-b3a95caf-20250113</b> - 2025-01-14
</li>
<li>
<b>19.1.0-canary-b158439a-20250115</b> - 2025-01-15
</li>
<li>
<b>19.1.0-canary-ae9017ce-20250122</b> - 2025-01-23
</li>
<li>
<b>19.1.0-canary-a84862db-20250218</b> - 2025-02-19
</li>
<li>
<b>19.1.0-canary-a4f9bd58-20250319</b> - 2025-03-20
</li>
<li>
<b>19.1.0-canary-a4b2d0d5-20250203</b> - 2025-02-03
</li>
<li>
<b>19.1.0-canary-9ff42a87-20250130</b> - 2025-01-31
</li>
<li>
<b>19.1.0-canary-9eabb373-20250124</b> - 2025-01-27
</li>
<li>
<b>19.1.0-canary-9b62ee71-20250122</b> - 2025-01-22
</li>
<li>
<b>19.1.0-canary-97d79495-20241223</b> - 2024-12-24
</li>
<li>
<b>19.1.0-canary-9463d51e-20241219</b> - 2024-12-19
</li>
<li>
<b>19.1.0-canary-93b58361-20250209</b> - 2025-02-10
</li>
<li>
<b>19.1.0-canary-8a7b487e-20250218</b> - 2025-02-18
</li>
<li>
<b>19.1.0-canary-8759c5c8-20250207</b> - 2025-02-07
</li>
<li>
<b>19.1.0-canary-7eb8234f-20241218</b> - 2024-12-18
</li>
<li>
<b>19.1.0-canary-7b402084-20250107</b> - 2025-01-07
</li>
<li>
<b>19.1.0-canary-74ea0c73-20250109</b> - 2025-01-09
</li>
<li>
<b>19.1.0-canary-740a4f7a-20250325</b> - 2025-03-25
</li>
<li>
<b>19.1.0-canary-7130d0c6-20241212</b> - 2024-12-12
</li>
<li>
<b>19.1.0-canary-6aa8254b-20250312</b> - 2025-03-12
</li>
<li>
<b>19.1.0-canary-694d3e1a-20241231</b> - 2025-01-01
</li>
<li>
<b>19.1.0-canary-6907aa2a-20241220</b> - 2024-12-23
</li>
<li>
<b>19.1.0-canary-662957cc-20250221</b> - 2025-02-21
</li>
<li>
<b>19.1.0-canary-62208bee-20250102</b> - 2025-01-02
</li>
<li>
<b>19.1.0-canary-5b51a2b9-20250116</b> - 2025-01-16
</li>
<li>
<b>19.1.0-canary-540efebc-20250112</b> - 2025-01-12
</li>
<li>
<b>19.1.0-canary-5398b711-20250314</b> - 2025-03-14
</li>
<li>
<b>19.1.0-canary-518d06d2-20241219</b> - 2024-12-19
</li>
<li>
<b>19.1.0-canary-4dff0e62-20241213</b> - 2024-12-13
</li>
<li>
<b>19.1.0-canary-4632e36a-20250216</b> - 2025-02-17
</li>
<li>
<b>19.1.0-canary-443b7ff2-20250303</b> - 2025-03-04
</li>
<li>
<b>19.1.0-canary-4280563b-20250326</b> - 2025-03-27
</li>
<li>
<b>19.1.0-canary-42687267-20250108</b> - 2025-01-08
</li>
<li>
<b>19.1.0-canary-3ce77d55-20250106</b> - 2025-01-06
</li>
<li>
<b>19.1.0-canary-3b009b4c-20250102</b> - 2025-01-03
</li>
<li>
<b>19.1.0-canary-37906d4d-20250127</b> - 2025-01-28
</li>
<li>
<b>19.1.0-canary-32b0cad8-20250213</b> - 2025-02-13
</li>
<li>
<b>19.1.0-canary-313332d1-20250326</b> - 2025-03-26
</li>
<li>
<b>19.1.0-canary-2980f277-20250301</b> - 2025-03-03
</li>
<li>
<b>19.1.0-canary-25677265-20250224</b> - 2025-02-24
</li>
<li>
<b>19.1.0-canary-22e39ea7-20250225</b> - 2025-02-25
</li>
<li>
<b>19.1.0-canary-18eaf51b-20250118</b> - 2025-01-20
</li>
<li>
<b>19.1.0-canary-130095f7-20241212</b> - 2024-12-12
</li>
<li>
<b>19.1.0-canary-0ca3deeb-20250311</b> - 2025-03-11
</li>
<li>
<b>19.1.0-canary-0a82580b-20250203</b> - 2025-02-04
</li>
<li>
<b>19.1.0-canary-056073de-20250109</b> - 2025-01-10
</li>
<li>
<b>19.1.0-canary-029e8bd6-20250306</b> - 2025-03-06
</li>
<li>
<b>19.0.0</b> - <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Freleases%2Ftag%2Fv19.0.0">2024-12-05</a></br><p>Below
is a list of all new features, APIs, deprecations, and breaking changes.
Read <a href="/api/browser/proxy?url=https%3A%2F%2Freact.dev%2Fblog%2F2024%2F04%2F25%2Freact-19"
rel="nofollow">React 19 release post</a> and <a
href="/api/browser/proxy?url=https%3A%2F%2Freact.dev%2Fblog%2F2024%2F04%2F25%2Freact-19-upgrade-guide"
rel="nofollow">React 19 upgrade guide</a> for more information.</p>
<blockquote>
<p>Note: To help make the upgrade to React 19 easier, we’ve published a
[email protected] release that is identical to 18.2 but adds warnings for
deprecated APIs and other changes that are needed for React 19. We
recommend upgrading to React 18.3.1 first to help identify any issues
before upgrading to React 19.</p>
</blockquote>
<h2>New Features</h2>
<h3>React</h3>
<ul>
<li>Actions: <code>startTransition</code> can now accept async
functions. Functions passed to <code>startTransition</code> are called
“Actions”. A given Transition can include one or more Actions which
update state in the background and update the UI with one commit. In
addition to updating state, Actions can now perform side effects
including async requests, and the Action will wait for the work to
finish before finishing the Transition. This feature allows Transitions
to include side effects like <code>fetch()</code> in the pending state,
and provides support for error handling, and optimistic updates.</li>
<li><code>useActionState</code>: is a new hook to order Actions inside
of a Transition with access to the state of the action, and the pending
state. It accepts a reducer that can call Actions, and the initial state
used for first render. It also accepts an optional string that is used
if the action is passed to a form <code>action</code> prop to support
progressive enhancement in forms.</li>
<li><code>useOptimistic</code>: is a new hook to update state while a
Transition is in progress. It returns the state, and a set function that
can be called inside a transition to “optimistically” update the state
to expected final value immediately while the Transition completes in
the background. When the transition finishes, the state is updated to
the new value.</li>
<li><code>use</code>: is a new API that allows reading resources in
render. In React 19, <code>use</code> accepts a promise or Context. If
provided a promise, <code>use</code> will suspend until a value is
resolved. <code>use</code> can only be used in render but can be called
conditionally.</li>
<li><code>ref</code> as a prop: Refs can now be used as props, removing
the need for <code>forwardRef</code>.</li>
<li><strong>Suspense sibling pre-warming</strong>: When a component
suspends, React will immediately commit the fallback of the nearest
Suspense boundary, without waiting for the entire sibling tree to
render. After the fallback commits, React will schedule another render
for the suspended siblings to “pre-warm” lazy requests.</li>
</ul>
<h3>React DOM Client</h3>
<ul>
<li><code><form> action</code> prop: Form Actions allow you to
manage forms automatically and integrate with
<code>useFormStatus</code>. When a <code><form> action</code>
succeeds, React will automatically reset the form for uncontrolled
components. The form can be reset manually with the new
<code>requestFormReset</code> API.</li>
<li><code><button> and <input> formAction</code> prop:
Actions can be passed to the <code>formAction</code> prop to configure
form submission behavior. This allows using different Actions depending
on the input.</li>
<li><code>useFormStatus</code>: is a new hook that provides the status
of the parent <code><form> action</code>, as if the form was a
Context provider. The hook returns the values: <code>pending</code>,
<code>data</code>, <code>method</code>, and <code>action</code>.</li>
<li>Support for Document Metadata: We’ve added support for rendering
document metadata tags in components natively. React will automatically
hoist them into the <code><head></code> section of the
document.</li>
<li>Support for Stylesheets: React 19 will ensure stylesheets are
inserted into the <code><head></code> on the client before
revealing the content of a Suspense boundary that depends on that
stylesheet.</li>
<li>Support for async scripts: Async scripts can be rendered anywhere in
the component tree and React will handle ordering and
deduplication.</li>
<li>Support for preloading resources: React 19 ships with
<code>preinit</code>, <code>preload</code>, <code>prefetchDNS</code>,
and <code>preconnect</code> APIs to optimize initial page loads by
moving discovery of additional resources like fonts out of stylesheet
loading. They can also be used to prefetch resources used by an
anticipated navigation.</li>
</ul>
<h3>React DOM Server</h3>
<ul>
<li>Added <code>prerender</code> and <code>prerenderToNodeStream</code>
APIs for static site generation. They are designed to work with
streaming environments like Node.js Streams and Web Streams. Unlike
<code>renderToString</code>, they wait for data to load for HTML
generation.</li>
</ul>
<h3>React Server Components</h3>
<ul>
<li>RSC features such as directives, server components, and server
functions are now stable. This means libraries that ship with Server
Components can now target React 19 as a peer dependency with a
react-server export condition for use in frameworks that support the
Full-stack React Architecture. The underlying APIs used to implement a
React Server Components bundler or framework do not follow semver and
may break between minors in React 19.x. See <a
href="/api/browser/proxy?url=https%3A%2F%2F19.react.dev%2Freference%2Frsc%2Fserver-components"
rel="nofollow">docs</a> for how to support React Server Components.</li>
</ul>
<h2>Deprecations</h2>
<ul>
<li>Deprecated: <code>element.ref</code> access: React 19 supports ref
as a prop, so we’re deprecating <code>element.ref</code> in favor of
<code>element.props.ref</code>. Accessing will result in a warning.</li>
<li><code>react-test-renderer</code>: In React 19, react-test-renderer
logs a deprecation warning and has switched to concurrent rendering for
web usage. We recommend migrating your tests to @
testinglibrary.com/docs/react-testing-library/intro/) or @
testingesting-library.com/docs/react-native-testing-library/intro)</li>
</ul>
<h2>Breaking Changes</h2>
<p>React 19 brings in a number of breaking changes, including the
removals of long-deprecated APIs. We recommend first upgrading to
<code>18.3.1</code>, where we've added additional deprecation warnings.
Check out the <a
href="/api/browser/proxy?url=https%3A%2F%2F19.react.dev%2Fblog%2F2024%2F04%2F25%2Freact-19-upgrade-guide"
rel="nofollow">upgrade guide</a> for more details and guidance on
codemodding.</p>
<h3>React</h3>
<ul>
<li>New JSX Transform is now required: We introduced <a
href="/api/browser/proxy?url=https%3A%2F%2Flegacy.reactjs.org%2Fblog%2F2020%2F09%2F22%2Fintroducing-the-new-jsx-transform.html"
rel="nofollow">a new JSX transform</a> in 2020 to improve bundle size
and use JSX without importing React. In React 19, we’re adding
additional improvements like using ref as a prop and JSX speed
improvements that require the new transform.</li>
<li>Errors in render are not re-thrown: Errors that are not caught by an
Error Boundary are now reported to window.reportError. Errors that are
caught by an Error Boundary are reported to console.error. We’ve
introduced <code>onUncaughtError</code> and <code>onCaughtError</code>
methods to <code>createRoot</code> and <code>hydrateRoot</code> to
customize this error handling.</li>
<li>Removed: <code>propTypes</code>: Using <code>propTypes</code> will
now be silently ignored. If required, we recommend migrating to
TypeScript or another type-checking solution.</li>
<li>Removed: <code>defaultProps</code> for functions: ES6 default
parameters can be used in place. Class components continue to support
<code>defaultProps</code> since there is no ES6 alternative.</li>
<li>Removed: <code>contextTypes</code> and <code>getChildContext</code>:
Legacy Context for class components has been removed in favor of the
<code>contextType</code> API.</li>
<li>Removed: string refs: Any usage of string refs need to be migrated
to ref callbacks.</li>
<li>Removed: Module pattern factories: A rarely used pattern that can be
migrated to regular functions.</li>
<li>Removed: <code>React.createFactory</code>: Now that JSX is broadly
supported, all <code>createFactory</code> usage can be migrated to JSX
components.</li>
<li>Removed: <code>react-test-renderer/shallow</code>: This has been a
re-export of <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fenzymejs%2Freact-shallow-renderer">react-shallow-renderer</a>
since React 18. If needed, you can continue to use the third-party
package directly. We recommend using @
testinglibrary.com/docs/react-testing-library/intro/) or @
testingesting-library.com/docs/react-native-testing-library/intro)
instead.</li>
</ul>
<h3>React DOM</h3>
<ul>
<li>Removed: <code>react-dom/test-utils</code>: We’ve moved
<code>act</code> from <code>react-dom/test-utils</code> to react. All
other utilities have been removed.</li>
<li>Removed: <code>ReactDOM</code>.<code>render</code>,
<code>ReactDOM</code>.<code>hydrate</code>: These have been removed in
favor of the concurrent equivalents:
<code>ReactDOM</code>.<code>createRoot</code> and
<code>ReactDOM.hydrateRoot</code>.</li>
<li>Removed: <code>unmountComponentAtNode</code>: Removed in favor of
<code>root.unmount()</code>.</li>
<li>Removed: <code>ReactDOM</code>.<code>findDOMNode</code>: You can
replace <code>ReactDOM</code>.<code>findDOMNode</code> with DOM
Refs.</li>
</ul>
<h2>Notable Changes</h2>
<h3>React</h3>
<ul>
<li><code><Context></code> as a provider: You can now render
<code><Context></code> as a provider instead of
<code><Context.Provider></code>.</li>
<li>Cleanup functions for refs: When the component unmounts, React will
call the cleanup function returned from the ref callback.</li>
<li><code>useDeferredValue</code> initial value argument: When provided,
<code>useDeferredValue</code> will return the initial value for the
initial render of a component, then schedule a re-render in the
background with the <code>deferredValue</code> returned.</li>
<li>Support for Custom Elements: React 19 now passes all tests on <a
href="/api/browser/proxy?url=https%3A%2F%2Fcustom-elements-everywhere.com%2F" rel="nofollow">Custom
Elements Everywhere</a>.</li>
<li>StrictMode changes: <code>useMemo</code> and
<code>useCallback</code> will now reuse the memoized results from the
first render, during the second render. Additionally, StrictMode will
now double-invoke ref callback functions on initial mount.</li>
<li>UMD builds removed: To load React 19 with a script tag, we recommend
using an ESM-based CDN such as <a href="/api/browser/proxy?url=http%3A%2F%2Fesm.sh"
rel="nofollow">esm.sh</a>.</li>
</ul>
<h3>React DOM</h3>
<ul>
<li>Diffs for hydration errors: In the case of a mismatch, React 19 logs
a single error with a diff of the mismatched content.</li>
<li>Compatibility with third-party scripts and extensions: React will
now force a client re-render to fix up any mismatched content caused by
elements inserted by third-party JS.</li>
</ul>
<h2>TypeScript Changes</h2>
<p>The most common changes can be codemodded with <code>npx
types-react-codemod@latest preset-19
./path-to-your-react-ts-files</code>.</p>
<ul>
<li>Removed deprecated TypeScript types:
<ul>
<li><code>ReactChild</code> (replacement: <code>React.ReactElement |
number | string)</code></li>
<li><code>ReactFragment</code> (replacement:
<code>Iterable<React.ReactNode></code>)</li>
<li><code>ReactNodeArray</code> (replacement:
<code>ReadonlyArray<React.ReactNode></code>)</li>
<li><code>ReactText</code> (replacement: <code>number |
string</code>)</li>
<li><code>VoidFunctionComponent</code> (replacement:
<code>FunctionComponent</code>)</li>
<li><code>VFC</code> (replacement: <code>FC</code>)</li>
<li>Moved to <code>prop-types</code>: <code>Requireable</code>,
<code>ValidationMap</code>, <code>Validator</code>,
<code>WeakValidationMap</code></li>
<li>Moved to <code>create-react-class</code>:
<code>ClassicComponentClass</code>, <code>ClassicComponent</code>,
<code>ClassicElement</code>, <code>ComponentSpec</code>,
<code>Mixin</code>, <code>ReactChildren</code>, <code>ReactHTML</code>,
<code>ReactSVG</code>, <code>SFCFactory</code></li>
</ul>
</li>
<li>Disallow implicit return in refs: refs can now accept cleanup
functions. When you return something else, we can’t tell if you
intentionally returned something not meant to clean up or returned the
wrong value. Implicit returns of anything but functions will now
error.</li>
<li>Require initial argument to <code>useRef</code>: The initial
argument is now required to match <code>useState</code>,
<code>createContext</code> etc</li>
<li>Refs are mutable by default: Ref objects returned from
<code>useRef()</code> are now always mutable instead of sometimes being
immutable. This feature was too confusing for users and conflicted with
legit cases where refs were managed by React and manually written
to.</li>
<li>Strict <code>ReactElement</code> typing: The props of React elements
now default to <code>unknown</code> instead of <code>any</code> if the
element is typed as <code>ReactElement</code></li>
<li>JSX namespace in TypeScript: The global <code>JSX</code> namespace
is removed to improve interoperability with other libraries using JSX.
Instead, the JSX namespace is available from the React package:
<code>import { JSX } from 'react'</code></li>
<li>Better <code>useReducer</code> typings: Most <code>useReducer</code>
usage should not require explicit type arguments.<br>
For example,
<div class="highlight highlight-source-diff notranslate
position-relative overflow-auto"
data-snippet-clipboard-copy-content="-useReducer<React.Reducer<State,
Action>>(reducer)
+useReducer(reducer) "><pre><span class="pl-md"><span
class="pl-md">-</span>useReducer<React.Reducer<State,
Action>>(reducer) </span>
<span class="pl-mi1"><span class="pl-mi1">+</span>useReducer(reducer)
</span></pre></div>
or
<div class="highlight highlight-source-diff notranslate
position-relative overflow-auto"
data-snippet-clipboard-copy-content="-useReducer<React.Reducer<State,
Action>>(reducer)
+useReducer<State, [Action]>(reducer)"><pre><span
class="pl-md"><span
class="pl-md">-</span>useReducer<React.Reducer<State,
Action>>(reducer) </span>
<span class="pl-mi1"><span class="pl-mi1">+</span>useReducer<State,
[Action]>(reducer)</span></pre></div>
</li>
</ul>
<h2>All Changes</h2>
<h3>React</h3>
<ul>
<li>Add support for async Actions (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26621"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26621/hovercard">#26621</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26726"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26726/hovercard">#26726</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28078"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28078/hovercard">#28078</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28097"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28097/hovercard">#28097</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29226"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29226/hovercard">#29226</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29618"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29618/hovercard">#29618</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29670"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29670/hovercard">#29670</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26716"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26716/hovercard">#26716</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a> and <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sebmarkbage/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsebmarkbage">@ sebmarkbage</a>)</li>
<li>Add <code>useActionState()</code> hook to update state based on the
result of a Form Action (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27270"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27270/hovercard">#27270</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27278"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27278/hovercard">#27278</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27309"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27309/hovercard">#27309</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27302"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27302/hovercard">#27302</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27307"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27307/hovercard">#27307</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27366"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27366/hovercard">#27366</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27370"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27370/hovercard">#27370</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27321"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27321/hovercard">#27321</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27374"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27374/hovercard">#27374</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27372"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27372/hovercard">#27372</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27397"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27397/hovercard">#27397</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27399"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27399/hovercard">#27399</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27460"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27460/hovercard">#27460</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28557"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28557/hovercard">#28557</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27570"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27570/hovercard">#27570</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27571"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27571/hovercard">#27571</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28631"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28631/hovercard">#28631</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28788"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28788/hovercard">#28788</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29694"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29694/hovercard">#29694</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29695"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29695/hovercard">#29695</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29694"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29694/hovercard">#29694</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F29665"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/29665/hovercard">#29665</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28232"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28232/hovercard">#28232</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28319"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28319/hovercard">#28319</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/eps1lon/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Feps1lon">@ eps1lon</a>, and <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/rickhanlonii/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Frickhanlonii">@ rickhanlonii</a>)</li>
<li>Add <code>use()</code> API to read resources in render (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25084"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25084/hovercard">#25084</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25202"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25202/hovercard">#25202</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25207"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25207/hovercard">#25207</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25214"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25214/hovercard">#25214</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25226"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25226/hovercard">#25226</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25247"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25247/hovercard">#25247</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25539"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25539/hovercard">#25539</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25538"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25538/hovercard">#25538</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25537"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25537/hovercard">#25537</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25543"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25543/hovercard">#25543</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25561"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25561/hovercard">#25561</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25620"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25620/hovercard">#25620</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25615"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25615/hovercard">#25615</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25922"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25922/hovercard">#25922</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25641"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25641/hovercard">#25641</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25634"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25634/hovercard">#25634</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26232"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26232/hovercard">#26232</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26535"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26535/hovercard">#26536</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26739"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26739/hovercard">#26739</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28233"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28233/hovercard">#28233</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/mofeiZ/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2FmofeiZ">@ mofeiZ</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sebmarkbage/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsebmarkbage">@ sebmarkbage</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sophiebits/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsophiebits">@ sophiebits</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/eps1lon/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Feps1lon">@ eps1lon</a>, and <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/hansottowirtz/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fhansottowirtz">@
hansottowirtz</a>)</li>
<li>Add <code>useOptimistic()</code> hook to display mutated state
optimistically during an async mutation (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26740"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26740/hovercard">#26740</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26772"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26772/hovercard">#26772</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27277"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27277/hovercard">#27277</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27453"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27453/hovercard">#27453</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27454"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27454/hovercard">#27454</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27936"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27936/hovercard">#27936</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Added an <code>initialValue</code> argument to
<code>useDeferredValue()</code> hook (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27500"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27500/hovercard">#27500</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27509"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27509/hovercard">#27509</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27512"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27512/hovercard">#27512</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27888"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27888/hovercard">#27888</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27550"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27550/hovercard">#27550</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Support refs as props, warn on <code>element.ref</code> access (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28348"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28348/hovercard">#28348</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28464"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28464/hovercard">#28464</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28731"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28731/hovercard">#28731</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Support Custom Elements (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F22184"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/22184/hovercard">#22184</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26524"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26524/hovercard">#26524</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26523"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26523/hovercard">#26523</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27511"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27511/hovercard">#27511</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F24541"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/24541/hovercard">#24541</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/josepharhar/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fjosepharhar">@ josepharhar</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sebmarkbage/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsebmarkbage">@ sebmarkbage</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/gnoff/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fgnoff">@ gnoff</a> and <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/eps1lon/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Feps1lon">@ eps1lon</a>)</li>
<li>Add ref cleanup function (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25686"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25686/hovercard">#25686</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28883"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28883/hovercard">#28883</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28910"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28910/hovercard">#28910</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sammy-SC/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsammy-SC">@ sammy-SC</a>), <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/jackpope/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fjackpope">@ jackpope</a>, and <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/kassens/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fkassens">@ kassens</a>)</li>
<li>Sibling pre-rendering replaced by sibling pre-warming (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26380"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26380/hovercard">#26380</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26549"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26549/hovercard">#26549</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F30761"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/30761/hovercard">#30761</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F30800"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/30800/hovercard">#30800</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F30762"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/30762/hovercard">#30762</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F30879"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/30879/hovercard">#30879</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F30934"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/30934/hovercard">#30934</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F30952"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/30952/hovercard">#30952</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31056"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31056/hovercard">#31056</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F31452"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/31452/hovercard">#31452</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sammy-SC/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsammy-SC">@ sammy-SC</a>), <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/gnoff/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fgnoff">@ gnoff</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/jackpope/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fjackpope">@ jackpope</a>, <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/rickhanlonii/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Frickhanlonii">@ rickhanlonii</a>)</li>
<li>Don’t rethrow errors at the root (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28627"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28627/hovercard">#28627</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28641"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28641/hovercard">#28641</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sebmarkbage/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsebmarkbage">@ sebmarkbage</a>)</li>
<li>Batch sync discrete, continuous, and default lanes (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25700"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25700/hovercard">#25700</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/tyao1/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ftyao1">@ tyao1</a>)</li>
<li>Switch <code><Context></code> to mean
<code><Context.Provider></code> (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28226"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28226/hovercard">#28226</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/gaearon/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fgaearon">@ gaearon</a>)</li>
<li>Changes to <em>StrictMode</em>
<ul>
<li>Handle <code>info</code>, <code>group</code>, and
<code>groupCollapsed</code> in <em>StrictMode</em> logging (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25172"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25172/hovercard">#25172</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/timneutkens/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ftimneutkens">@ timneutkens</a>)</li>
<li>Refs are now attached/detached/attached in <em>StrictMode</em> (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25049"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25049/hovercard">#25049</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sammy-SC/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsammy-SC">@ sammy-SC</a>)</li>
<li>Fix <code>useSyncExternalStore()</code> hydration in
<em>StrictMode</em> (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26791"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26791/hovercard">#26791</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sophiebits/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsophiebits">@ sophiebits</a>)</li>
<li>Always trigger <code>componentWillUnmount()</code> in
<em>StrictMode</em> (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26842"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26842/hovercard">#26842</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/tyao1/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ftyao1">@ tyao1</a>)</li>
<li>Restore double invoking <code>useState()</code> and
<code>useReducer()</code> initializer functions in <em>StrictMode</em>
(<a href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F28248"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/28248/hovercard">#28248</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/eps1lon/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Feps1lon">@ eps1lon</a>)</li>
<li>Reuse memoized result from first pass (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25583"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25583/hovercard">#25583</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Fix <code>useId()</code> in <em>StrictMode</em> (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25713"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25713/hovercard">#25713</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/gnoff/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fgnoff">@ gnoff</a>)</li>
<li>Add component name to <em>StrictMode</em> error messages (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25718"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25718/hovercard">#25718</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sammy-SC/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsammy-SC">@ sammy-SC</a>)</li>
</ul>
</li>
<li>Add support for rendering BigInt (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F24580"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/24580/hovercard">#24580</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/eps1lon/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Feps1lon">@ eps1lon</a>)</li>
<li><code>act()</code> no longer checks <code>shouldYield</code> which
can be inaccurate in test environments (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26317"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26317/hovercard">#26317</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Warn when keys are spread with props (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25697"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25697/hovercard">#25697</a>, <a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26080"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26080/hovercard">#26080</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/sebmarkbage/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fsebmarkbage">@ sebmarkbage</a> and <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/kassens/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fkassens">@ kassens</a>)</li>
<li>Generate sourcemaps for production build artifacts (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26446"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26446/hovercard">#26446</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/markerikson/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fmarkerikson">@ markerikson</a>)</li>
<li>Improve stack diffing algorithm (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F27132"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/27132/hovercard">#27132</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/KarimP/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2FKarimP">@ KarimP</a>)</li>
<li>Suspense throttling lowered from 500ms to 300ms (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26803"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26803/hovercard">#26803</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Lazily propagate context changes (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F20890"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/20890/hovercard">#20890</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a> and <a
class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/gnoff/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Fgnoff">@ gnoff</a>)</li>
<li>Immediately rerender pinged fiber (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F25074"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/25074/hovercard">#25074</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Move update scheduling to microtask (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2Freact%2Fpull%2F26512"
data-hovercard-type="pull_request"
data-hovercard-url="/facebook/react/pull/26512/hovercard">#26512</a> by
<a class="user-mention notranslate" data-hovercard-type="user"
data-hovercard-url="/users/acdlite/hovercard"
data-octo-click="hovercard-link-click"
data-octo-dimensions="link_type:self"
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Facdlite">@ acdlite</a>)</li>
<li>Consistently apply throttled retries (<a
href="/api/browser/proxy?url=https%3A%2F%2Fredirect.github.com%2Ffacebook%2F%E2%80%A6%3C%2Fpre%3E%0A%20%20%20%20%3C%2Fdiv%3E%0A%3C%2Fdiv%3E%0A%0A%20%20%20%20%3C%2Fdiv%3E%0A%20%20%3C%2Fdiv%3E%0A%3C%2Fdiv%3E%0A%0A%20%20%3Cdiv%20class%3D"TimelineItem">
ahacop
added a commit
to changebot-ai/widgets
that referenced
this pull request
Aug 24, 2026
[cb skip] Packages updated: - react 18.3.1 -> 19.2.8 (dev) - react-dom 18.3.1 -> 19.2.8 (dev) - @types/react 18.3.26 -> 19.2.18 (dev) - @types/react-dom 18.3.7 -> 19.2.4 (dev) These are dev dependencies of @changebot/widgets-react, used to compile the generated wrappers. The peer range stays >=16.8.0. react-demo.html keeps loading React 18 from unpkg because React 19 publishes no UMD build, and that page uses the custom elements directly rather than the wrapper. == 19.2.7 (June 1, 2026) == React Server Components - Fixed missing `FormData` entries in Server Actions which regressed in 19.2.6 (@unstubbable [#36566](https://github.com/facebook/react/pull/36566)) == 19.2.6 (May 6, 2026) == React Server Components - Type hardening and performance improvements (@eps1lon, @unstubbable [#36425](https://github.com/facebook/react/pull/36425)) == 19.2.5 (March 18, 2026) == React Server Components - Add more cycle protections (@eps1lon, @unstubbable [#36236](https://github.com/facebook/react/pull/36236)) == 19.2.4 (Jan 26, 2026) == React Server Components - Add more DoS mitigations to Server Actions, and harden Server Components (@gnoff, @lubieowoce, @sebmarkbage, @unstubbable [#35632](https://github.com/facebook/react/pull/35632)) == 19.2.3 (Dec 11, 2025) == React Server Components - Add extra loop protection to React Server Functions (@sebmarkbage [#35351](https://github.com/facebook/react/pull/35351)) == 19.2.2 (Dec 11, 2025) == React Server Components - Move `react-server-dom-webpack/*.unbundled` to private `react-server-dom-unbundled` (@eps1lon [#35290](https://github.com/facebook/react/pull/35290)) - Patch Promise cycles and toString on Server Functions (@sebmarkbage, @unstubbable [#35289](https://github.com/facebook/react/pull/35289), [#35345](https://github.com/facebook/react/pull/35345)) == 19.2.1 (Dec 3, 2025) == React Server Components - Bring React Server Component fixes to Server Actions (@sebmarkbage [#35277](https://github.com/facebook/react/pull/35277)) == 19.2.0 (October 1st, 2025) Below is a list of all new features, APIs, and bug fixes. Read the [React 19.2 release post](https://react.dev/blog/2025/10/01/react-19-2) for more information. == New React Features - [`<Activity>`](https://react.dev/reference/react/Activity): A new API to hide and restore the UI and internal state of its children. - [`useEffectEvent`](https://react.dev/reference/react/useEffectEvent) is a React Hook that lets you extract non-reactive logic into an [Effect Event](https://react.dev/learn/separating-events-from-effects#declaring-an-effect-event). - [`cacheSignal`](https://react.dev/reference/react/cacheSignal) (for RSCs) lets your know when the `cache()` lifetime is over. - [React Performance tracks](https://react.dev/reference/dev-tools/react-performance-tracks) appear on the Performance panel’s timeline in your browser developer tools == New React DOM Features - Added resume APIs for partial pre-rendering with Web Streams: - [`resume`](https://react.dev/reference/react-dom/server/resume): to resume a prerender to a stream. - [`resumeAndPrerender`](https://react.dev/reference/react-dom/static/resumeAndPrerender): to resume a prerender to HTML. - Added resume APIs for partial pre-rendering with Node Streams: - [`resumeToPipeableStream`](https://react.dev/reference/react-dom/server/resumeToPipeableStream): to resume a prerender to a stream. - [`resumeAndPrerenderToNodeStream`](https://react.dev/reference/react-dom/static/resumeAndPrerenderToNodeStream): to resume a prerender to HTML. - Updated [`prerender`](https://react.dev/reference/react-dom/static/prerender) APIs to return a `postponed` state that can be passed to the `resume` APIs. == Notable changes - React DOM now batches suspense boundary reveals, matching the behavior of client side rendering. This change is especially noticeable when animating the reveal of Suspense boundaries e.g. with the upcoming `<ViewTransition>` Component. React will batch as much reveals as possible before the first paint while trying to hit popular first-contentful paint metrics. - Add Node Web Streams (`prerender`, `renderToReadableStream`) to server-side-rendering APIs for Node.js - Use underscore instead of `:` IDs generated by useId == All Changes == React - `<Activity />` was developed over many years, starting before `ClassComponent.setState` (@acdlite @sebmarkbage and many others) - Stringify context as "SomeContext" instead of "SomeContext.Provider" (@kassens [#33507](https://github.com/facebook/react/pull/33507)) - Include stack of cause of React instrumentation errors with `%o` placeholder (@eps1lon [#34198](https://github.com/facebook/react/pull/34198)) - Fix infinite `useDeferredValue` loop in popstate event (@acdlite [#32821](https://github.com/facebook/react/pull/32821)) - Fix a bug when an initial value was passed to `useDeferredValue` (@acdlite [#34376](https://github.com/facebook/react/pull/34376)) - Fix a crash when submitting forms with Client Actions (@sebmarkbage [#33055](https://github.com/facebook/react/pull/33055)) - Hide/unhide the content of dehydrated suspense boundaries if they resuspend (@sebmarkbage [#32900](https://github.com/facebook/react/pull/32900)) - Avoid stack overflow on wide trees during Hot Reload (@sophiebits [#34145](https://github.com/facebook/react/pull/34145)) - Improve Owner and Component stacks in various places (@sebmarkbage, @eps1lon: [#33629](https://github.com/facebook/react/pull/33629), [#33724](https://github.com/facebook/react/pull/33724), [#32735](https://github.com/facebook/react/pull/32735), [#33723](https://github.com/facebook/react/pull/33723)) - Add `cacheSignal` (@sebmarkbage [#33557](https://github.com/facebook/react/pull/33557)) == React DOM - Block on Suspensey Fonts during reveal of server-side-rendered content (@sebmarkbage [#33342](https://github.com/facebook/react/pull/33342)) - Use underscore instead of `:` for IDs generated by `useId` (@sebmarkbage, @eps1lon: [#32001](https://github.com/facebook/react/pull/32001), [https://github.com/facebook/react/pull/33342](https://github.com/facebook/react/pull/33342)[#33099](https://github.com/facebook/react/pull/33099), [#33422](https://github.com/facebook/react/pull/33422)) - Stop warning when ARIA 1.3 attributes are used (@Abdul-Omira [#34264](https://github.com/facebook/react/pull/34264)) - Allow `nonce` to be used on hoistable styles (@Andarist [#32461](https://github.com/facebook/react/pull/32461)) - Warn for using a React owned node as a Container if it also has text content (@sebmarkbage [#32774](https://github.com/facebook/react/pull/32774)) - s/HTML/text for for error messages if text hydration mismatches (@rickhanlonii [#32763](https://github.com/facebook/react/pull/32763)) - Fix a bug with `React.use` inside `React.lazy`\-ed Component (@hi-ogawa [#33941](https://github.com/facebook/react/pull/33941)) - Enable the `progressiveChunkSize` option for server-side-rendering APIs (@sebmarkbage [#33027](https://github.com/facebook/react/pull/33027)) - Fix a bug with deeply nested Suspense inside Suspense fallback when server-side-rendering (@gnoff [#33467](https://github.com/facebook/react/pull/33467)) - Avoid hanging when suspending after aborting while rendering (@gnoff [#34192](https://github.com/facebook/react/pull/34192)) - Add Node Web Streams to server-side-rendering APIs for Node.js (@sebmarkbage [#33475](https://github.com/facebook/react/pull/33475)) == React Server Components - Preload `<img>` and `<link>` using hints before they're rendered (@sebmarkbage [#34604](https://github.com/facebook/react/pull/34604)) - Log error if production elements are rendered during development (@eps1lon [#34189](https://github.com/facebook/react/pull/34189)) - Fix a bug when returning a Temporary reference (e.g. a Client Reference) from Server Functions (@sebmarkbage [#34084](https://github.com/facebook/react/pull/34084), @denk0403 [#33761](https://github.com/facebook/react/pull/33761)) - Pass line/column to `filterStackFrame` (@eps1lon [#33707](https://github.com/facebook/react/pull/33707)) - Support Async Modules in Turbopack Server References (@lubieowoce [#34531](https://github.com/facebook/react/pull/34531)) - Add support for .mjs file extension in Webpack (@jennyscript [#33028](https://github.com/facebook/react/pull/33028)) - Fix a wrong missing key warning (@unstubbable [#34350](https://github.com/facebook/react/pull/34350)) - Make console log resolve in predictable order (@sebmarkbage [#33665](https://github.com/facebook/react/pull/33665)) == React Reconciler - [createContainer](https://github.com/facebook/react/blob/v19.2.0/packages/react-reconciler/src/ReactFiberReconciler.js#L255-L261) and [createHydrationContainer](https://github.com/facebook/react/blob/v19.2.0/packages/react-reconciler/src/ReactFiberReconciler.js#L305-L312) had their parameter order adjusted after `on*` handlers to account for upcoming experimental APIs == 19.1.8 (June 1, 2026) == React Server Components - Fixed missing `FormData` entries in Server Actions which regressed in 19.1.7 (@unstubbable [#36567](https://github.com/facebook/react/pull/36567)) == 19.1.7 (May 6, 2026) == React Server Components - Type hardening and performance improvements (@eps1lon, @unstubbable [#36425](https://github.com/facebook/react/pull/36425)) == 19.1.6 (March 18, 2026) == React Server Components - Add more cycle protections (@eps1lon, @unstubbable [#36236](https://github.com/facebook/react/pull/36236)) == 19.1.5 (Jan 26, 2026) == React Server Components - Add more DoS mitigations to Server Actions, and harden Server Components (@gnoff, @lubieowoce, @sebmarkbage, @unstubbable [#35632](https://github.com/facebook/react/pull/35632)) == 19.1.4 (Dec 11, 2025) == React Server Components - Add extra loop protection to React Server Functions (@sebmarkbage [#35351](https://github.com/facebook/react/pull/35351)) == 19.1.3 (Dec 11, 2025) == React Server Components - Move `react-server-dom-webpack/*.unbundled` to private `react-server-dom-unbundled` (@eps1lon [#35290](https://github.com/facebook/react/pull/35290)) - Patch Promise cycles and toString on Server Functions (@sebmarkbage, @unstubbable [#35289](https://github.com/facebook/react/pull/35289), [#35345](https://github.com/facebook/react/pull/35345)) == 19.1.2 (Dec 3, 2025) == React Server Components - Bring React Server Component fixes to Server Actions (@sebmarkbage [#35277](https://github.com/facebook/react/pull/35277)) == 19.1.1 (July 28, 2025) == React * Fixed Owner Stacks to work with ES2015 function.name semantics ([#33680](https://github.com/facebook/react/pull/33680) by @hoxyq) == 19.1.0 (March 28, 2025) == Owner Stack An Owner Stack is a string representing the components that are directly responsible for rendering a particular component. You can log Owner Stacks when debugging or use Owner Stacks to enhance error overlays or other development tools. Owner Stacks are only available in development builds. Component Stacks in production are unchanged. * An Owner Stack is a development-only stack trace that helps identify which components are responsible for rendering a particular component. An Owner Stack is distinct from a Component Stacks, which shows the hierarchy of components leading to an error. * The [captureOwnerStack API](https://react.dev/reference/react/captureOwnerStack) is only available in development mode and returns a Owner Stack, if available. The API can be used to enhance error overlays or log component relationships when debugging. [#29923](https://github.com/facebook/react/pull/29923), [#32353](https://github.com/facebook/react/pull/32353), [#30306](https://github.com/facebook/react/pull/30306), [#32538](https://github.com/facebook/react/pull/32538), [#32529](https://github.com/facebook/react/pull/32529), [#32538](https://github.com/facebook/react/pull/32538) == React * Enhanced support for Suspense boundaries to be used anywhere, including the client, server, and during hydration. [#32069](https://github.com/facebook/react/pull/32069), [#32163](https://github.com/facebook/react/pull/32163), [#32224](https://github.com/facebook/react/pull/32224), [#32252](https://github.com/facebook/react/pull/32252) * Reduced unnecessary client rendering through improved hydration scheduling [#31751](https://github.com/facebook/react/pull/31751) * Increased priority of client rendered Suspense boundaries [#31776](https://github.com/facebook/react/pull/31776) * Fixed frozen fallback states by rendering unfinished Suspense boundaries on the client. [#31620](https://github.com/facebook/react/pull/31620) * Reduced garbage collection pressure by improving Suspense boundary retries. [#31667](https://github.com/facebook/react/pull/31667) * Fixed erroneous “Waiting for Paint” log when the passive effect phase was not delayed [#31526](https://github.com/facebook/react/pull/31526) * Fixed a regression causing key warnings for flattened positional children in development mode. [#32117](https://github.com/facebook/react/pull/32117) * Updated `useId` to use valid CSS selectors, changing format from `:r123:` to `«r123»`. [#32001](https://github.com/facebook/react/pull/32001) * Added a dev-only warning for null/undefined created in useEffect, useInsertionEffect, and useLayoutEffect. [#32355](https://github.com/facebook/react/pull/32355) * Fixed a bug where dev-only methods were exported in production builds. React.act is no longer available in production builds. [#32200](https://github.com/facebook/react/pull/32200) * Improved consistency across prod and dev to improve compatibility with Google Closure Compiler and bindings [#31808](https://github.com/facebook/react/pull/31808) * Improve passive effect scheduling for consistent task yielding. [#31785](https://github.com/facebook/react/pull/31785) * Fixed asserts in React Native when passChildrenWhenCloningPersistedNodes is enabled for OffscreenComponent rendering. [#32528](https://github.com/facebook/react/pull/32528) * Fixed component name resolution for Portal [#32640](https://github.com/facebook/react/pull/32640) * Added support for beforetoggle and toggle events on the dialog element. [#32479](https://github.com/facebook/react/pull/32479) == React DOM * Fixed double warning when the `href` attribute is an empty string [#31783](https://github.com/facebook/react/pull/31783) * Fixed an edge case where `getHoistableRoot()` didn’t work properly when the container was a Document [#32321](https://github.com/facebook/react/pull/32321) * Removed support for using HTML comments (e.g. `<!-- -->`) as a DOM container. [#32250](https://github.com/facebook/react/pull/32250) * Added support for `<script>` and `<template>` tags to be nested within `<select>` tags. [#31837](https://github.com/facebook/react/pull/31837) * Fixed responsive images to be preloaded as HTML instead of headers [#32445](https://github.com/facebook/react/pull/32445) == use-sync-external-store * Added `exports` field to `package.json` for `use-sync-external-store` to support various entrypoints. [#25231](https://github.com/facebook/react/pull/25231) == React Server Components * Added `unstable_prerender`, a new experimental API for prerendering React Server Components on the server [#31724](https://github.com/facebook/react/pull/31724) * Fixed an issue where streams would hang when receiving new chunks after a global error [#31840](https://github.com/facebook/react/pull/31840), [#31851](https://github.com/facebook/react/pull/31851) * Fixed an issue where pending chunks were counted twice. [#31833](https://github.com/facebook/react/pull/31833) * Added support for streaming in edge environments [#31852](https://github.com/facebook/react/pull/31852) * Added support for sending custom error names from a server so that they are available in the client for console replaying. [#32116](https://github.com/facebook/react/pull/32116) * Updated the server component wire format to remove IDs for hints and console.log because they have no return value [#31671](https://github.com/facebook/react/pull/31671) * Exposed `registerServerReference` in client builds to handle server references in different environments. [#32534](https://github.com/facebook/react/pull/32534) * Added react-server-dom-parcel package which integrates Server Components with the [Parcel bundler](https://parceljs.org/) [#31725](https://github.com/facebook/react/pull/31725), [#32132](https://github.com/facebook/react/pull/32132), [#31799](https://github.com/facebook/react/pull/31799), [#32294](https://github.com/facebook/react/pull/32294), [#31741](https://github.com/facebook/react/pull/31741) == 19.0.7 (June 1, 2026) == React Server Components - Fixed missing `FormData` entries in Server Actions which regressed in 19.0.6 (@unstubbable [#36568](https://github.com/facebook/react/pull/36568)) == 19.0.6 (May 6, 2026) == React Server Components - Type hardening and performance improvements (@eps1lon, @unstubbable [#36425](https://github.com/facebook/react/pull/36425)) == 19.0.5 (March 18, 2026) == React Server Components - Add more cycle protections (@eps1lon, @unstubbable [#36236](https://github.com/facebook/react/pull/36236)) == 19.0.4 (Jan 26, 2026) == React Server Components - Add more DoS mitigations to Server Actions, and harden Server Components (@gnoff, @lubieowoce, @sebmarkbage, @unstubbable [#35632](https://github.com/facebook/react/pull/35632)) == 19.0.3 (Dec 11, 2025) == React Server Components - Add extra loop protection to React Server Functions (@sebmarkbage [#35351](https://github.com/facebook/react/pull/35351)) == 19.0.2 (Dec 11, 2025) == React Server Components - Patch Promise cycles and toString on Server Functions (@sebmarkbage, @unstubbable [#35289](https://github.com/facebook/react/pull/35289), [#35345](https://github.com/facebook/react/pull/35345)) == 19.0.1 (Dec 3, 2025) == React Server Components - Bring React Server Component fixes to Server Actions (@sebmarkbage [#35277](https://github.com/facebook/react/pull/35277)) == 19.0.0 (December 5, 2024) Below is a list of all new features, APIs, deprecations, and breaking changes. Read [React 19 release post](https://react.dev/blog/2024/04/25/react-19) and [React 19 upgrade guide](https://react.dev/blog/2024/04/25/react-19-upgrade-guide) for more information. > Note: To help make the upgrade to React 19 easier, we’ve published a [email protected] release that is identical to 18.2 but adds warnings for deprecated APIs and other changes that are needed for React 19. We recommend upgrading to React 18.3.1 first to help identify any issues before upgrading to React 19. == New Features == React * Actions: `startTransition` can now accept async functions. Functions passed to `startTransition` are called “Actions”. A given Transition can include one or more Actions which update state in the background and update the UI with one commit. In addition to updating state, Actions can now perform side effects including async requests, and the Action will wait for the work to finish before finishing the Transition. This feature allows Transitions to include side effects like `fetch()` in the pending state, and provides support for error handling, and optimistic updates. * `useActionState`: is a new hook to order Actions inside of a Transition with access to the state of the action, and the pending state. It accepts a reducer that can call Actions, and the initial state used for first render. It also accepts an optional string that is used if the action is passed to a form `action` prop to support progressive enhancement in forms. * `useOptimistic`: is a new hook to update state while a Transition is in progress. It returns the state, and a set function that can be called inside a transition to “optimistically” update the state to expected final value immediately while the Transition completes in the background. When the transition finishes, the state is updated to the new value. * `use`: is a new API that allows reading resources in render. In React 19, `use` accepts a promise or Context. If provided a promise, `use` will suspend until a value is resolved. `use` can only be used in render but can be called conditionally. * `ref` as a prop: Refs can now be used as props, removing the need for `forwardRef`. * **Suspense sibling pre-warming**: When a component suspends, React will immediately commit the fallback of the nearest Suspense boundary, without waiting for the entire sibling tree to render. After the fallback commits, React will schedule another render for the suspended siblings to “pre-warm” lazy requests. == React DOM Client * `<form> action` prop: Form Actions allow you to manage forms automatically and integrate with `useFormStatus`. When a `<form> action` succeeds, React will automatically reset the form for uncontrolled components. The form can be reset manually with the new `requestFormReset` API. * `<button> and <input> formAction` prop: Actions can be passed to the `formAction` prop to configure form submission behavior. This allows using different Actions depending on the input. * `useFormStatus`: is a new hook that provides the status of the parent `<form> action`, as if the form was a Context provider. The hook returns the values: `pending`, `data`, `method`, and `action`. * Support for Document Metadata: We’ve added support for rendering document metadata tags in components natively. React will automatically hoist them into the `<head>` section of the document. * Support for Stylesheets: React 19 will ensure stylesheets are inserted into the `<head>` on the client before revealing the content of a Suspense boundary that depends on that stylesheet. * Support for async scripts: Async scripts can be rendered anywhere in the component tree and React will handle ordering and deduplication. * Support for preloading resources: React 19 ships with `preinit`, `preload`, `prefetchDNS`, and `preconnect` APIs to optimize initial page loads by moving discovery of additional resources like fonts out of stylesheet loading. They can also be used to prefetch resources used by an anticipated navigation. == React DOM Server * Added `prerender` and `prerenderToNodeStream` APIs for static site generation. They are designed to work with streaming environments like Node.js Streams and Web Streams. Unlike `renderToString`, they wait for data to load for HTML generation. == React Server Components * RSC features such as directives, server components, and server functions are now stable. This means libraries that ship with Server Components can now target React 19 as a peer dependency with a react-server export condition for use in frameworks that support the Full-stack React Architecture. The underlying APIs used to implement a React Server Components bundler or framework do not follow semver and may break between minors in React 19.x. See [docs](https://19.react.dev/reference/rsc/server-components) for how to support React Server Components. == Deprecations * Deprecated: `element.ref` access: React 19 supports ref as a prop, so we’re deprecating `element.ref` in favor of `element.props.ref`. Accessing will result in a warning. * `react-test-renderer`: In React 19, react-test-renderer logs a deprecation warning and has switched to concurrent rendering for web usage. We recommend migrating your tests to [@testing-library/react](https://testing-library.com/docs/react-testing-library/intro/) or [@testing-library/react-native](https://testing-library.com/docs/react-native-testing-library/intro) == Breaking Changes React 19 brings in a number of breaking changes, including the removals of long-deprecated APIs. We recommend first upgrading to `18.3.1`, where we've added additional deprecation warnings. Check out the [upgrade guide](https://19.react.dev/blog/2024/04/25/react-19-upgrade-guide) for more details and guidance on codemodding. == React * New JSX Transform is now required: We introduced [a new JSX transform](https://legacy.reactjs.org/blog/2020/09/22/introducing-the-new-jsx-transform.html) in 2020 to improve bundle size and use JSX without importing React. In React 19, we’re adding additional improvements like using ref as a prop and JSX speed improvements that require the new transform. * Errors in render are not re-thrown: Errors that are not caught by an Error Boundary are now reported to window.reportError. Errors that are caught by an Error Boundary are reported to console.error. We’ve introduced `onUncaughtError` and `onCaughtError` methods to `createRoot` and `hydrateRoot` to customize this error handling. * Removed: `propTypes`: Using `propTypes` will now be silently ignored. If required, we recommend migrating to TypeScript or another type-checking solution. * Removed: `defaultProps` for functions: ES6 default parameters can be used in place. Class components continue to support `defaultProps` since there is no ES6 alternative. * Removed: `contextTypes` and `getChildContext`: Legacy Context for class components has been removed in favor of the `contextType` API. * Removed: string refs: Any usage of string refs need to be migrated to ref callbacks. * Removed: Module pattern factories: A rarely used pattern that can be migrated to regular functions. * Removed: `React.createFactory`: Now that JSX is broadly supported, all `createFactory` usage can be migrated to JSX components. * Removed: `react-test-renderer/shallow`: This has been a re-export of [react-shallow-renderer](https://github.com/enzymejs/react-shallow-renderer) since React 18\. If needed, you can continue to use the third-party package directly. We recommend using [@testing-library/react](https://testing-library.com/docs/react-testing-library/intro/) or [@testing-library/react-native](https://testing-library.com/docs/react-native-testing-library/intro) instead. == React DOM * Removed: `react-dom/test-utils`: We’ve moved `act` from `react-dom/test-utils` to react. All other utilities have been removed. * Removed: `ReactDOM`.`render`, `ReactDOM`.`hydrate`: These have been removed in favor of the concurrent equivalents: `ReactDOM`.`createRoot` and `ReactDOM.hydrateRoot`. * Removed: `unmountComponentAtNode`: Removed in favor of `root.unmount()`. * Removed: `ReactDOM`.`findDOMNode`: You can replace `ReactDOM`.`findDOMNode` with DOM Refs. == Notable Changes == React * `<Context>` as a provider: You can now render `<Context>` as a provider instead of `<Context.Provider>`. * Cleanup functions for refs: When the component unmounts, React will call the cleanup function returned from the ref callback. * `useDeferredValue` initial value argument: When provided, `useDeferredValue` will return the initial value for the initial render of a component, then schedule a re-render in the background with the `deferredValue` returned. * Support for Custom Elements: React 19 now passes all tests on [Custom Elements Everywhere](https://custom-elements-everywhere.com/). * StrictMode changes: `useMemo` and `useCallback` will now reuse the memoized results from the first render, during the second render. Additionally, StrictMode will now double-invoke ref callback functions on initial mount. * UMD builds removed: To load React 19 with a script tag, we recommend using an ESM-based CDN such as [esm.sh](http://esm.sh). == React DOM * Diffs for hydration errors: In the case of a mismatch, React 19 logs a single error with a diff of the mismatched content. * Compatibility with third-party scripts and extensions: React will now force a client re-render to fix up any mismatched content caused by elements inserted by third-party JS. == TypeScript Changes The most common changes can be codemodded with `npx types-react-codemod@latest preset-19 ./path-to-your-react-ts-files`. * Removed deprecated TypeScript types: * `ReactChild` (replacement: `React.ReactElement | number | string)` * `ReactFragment` (replacement: `Iterable<React.ReactNode>`) * `ReactNodeArray` (replacement: `ReadonlyArray<React.ReactNode>`) * `ReactText` (replacement: `number | string`) * `VoidFunctionComponent` (replacement: `FunctionComponent`) * `VFC` (replacement: `FC`) * Moved to `prop-types`: `Requireable`, `ValidationMap`, `Validator`, `WeakValidationMap` * Moved to `create-react-class`: `ClassicComponentClass`, `ClassicComponent`, `ClassicElement`, `ComponentSpec`, `Mixin`, `ReactChildren`, `ReactHTML`, `ReactSVG`, `SFCFactory` * Disallow implicit return in refs: refs can now accept cleanup functions. When you return something else, we can’t tell if you intentionally returned something not meant to clean up or returned the wrong value. Implicit returns of anything but functions will now error. * Require initial argument to `useRef`: The initial argument is now required to match `useState`, `createContext` etc * Refs are mutable by default: Ref objects returned from `useRef()` are now always mutable instead of sometimes being immutable. This feature was too confusing for users and conflicted with legit cases where refs were managed by React and manually written to. * Strict `ReactElement` typing: The props of React elements now default to `unknown` instead of `any` if the element is typed as `ReactElement` * JSX namespace in TypeScript: The global `JSX` namespace is removed to improve interoperability with other libraries using JSX. Instead, the JSX namespace is available from the React package: `import { JSX } from 'react'` * Better `useReducer` typings: Most `useReducer` usage should not require explicit type arguments. For example, ```diff -useReducer<React.Reducer<State, Action>>(reducer) +useReducer(reducer) ``` or ```diff -useReducer<React.Reducer<State, Action>>(reducer) +useReducer<State, Action>(reducer) ``` == All Changes == React * Add support for async Actions ([\#26621](https://github.com/facebook/react/pull/26621), [\#26726](https://github.com/facebook/react/pull/26726), [\#28078](https://github.com/facebook/react/pull/28078), [\#28097](https://github.com/facebook/react/pull/28097), [\#29226](https://github.com/facebook/react/pull/29226), [\#29618](https://github.com/facebook/react/pull/29618), [\#29670](https://github.com/facebook/react/pull/29670), [\#26716](https://github.com/facebook/react/pull/26716) by [@acdlite](https://github.com/acdlite) and [@sebmarkbage](https://github.com/sebmarkbage)) * Add `useActionState()` hook to update state based on the result of a Form Action ([\#27270](https://github.com/facebook/react/pull/27270), [\#27278](https://github.com/facebook/react/pull/27278), [\#27309](https://github.com/facebook/react/pull/27309), [\#27302](https://github.com/facebook/react/pull/27302), [\#27307](https://github.com/facebook/react/pull/27307), [\#27366](https://github.com/facebook/react/pull/27366), [\#27370](https://github.com/facebook/react/pull/27370), [\#27321](https://github.com/facebook/react/pull/27321), [\#27374](https://github.com/facebook/react/pull/27374), [\#27372](https://github.com/facebook/react/pull/27372), [\#27397](https://github.com/facebook/react/pull/27397), [\#27399](https://github.com/facebook/react/pull/27399), [\#27460](https://github.com/facebook/react/pull/27460), [\#28557](https://github.com/facebook/react/pull/28557), [\#27570](https://github.com/facebook/react/pull/27570), [\#27571](https://github.com/facebook/react/pull/27571), [\#28631](https://github.com/facebook/react/pull/28631), [\#28788](https://github.com/facebook/react/pull/28788), [\#29694](https://github.com/facebook/react/pull/29694), [\#29695](https://github.com/facebook/react/pull/29695), [\#29694](https://github.com/facebook/react/pull/29694), [\#29665](https://github.com/facebook/react/pull/29665), [\#28232](https://github.com/facebook/react/pull/28232), [\#28319](https://github.com/facebook/react/pull/28319) by [@acdlite](https://github.com/acdlite), [@eps1lon](https://github.com/eps1lon), and [@rickhanlonii](https://github.com/rickhanlonii)) * Add `use()` API to read resources in render ([\#25084](https://github.com/facebook/react/pull/25084), [\#25202](https://github.com/facebook/react/pull/25202), [\#25207](https://github.com/facebook/react/pull/25207), [\#25214](https://github.com/facebook/react/pull/25214), [\#25226](https://github.com/facebook/react/pull/25226), [\#25247](https://github.com/facebook/react/pull/25247), [\#25539](https://github.com/facebook/react/pull/25539), [\#25538](https://github.com/facebook/react/pull/25538), [\#25537](https://github.com/facebook/react/pull/25537), [\#25543](https://github.com/facebook/react/pull/25543), [\#25561](https://github.com/facebook/react/pull/25561), [\#25620](https://github.com/facebook/react/pull/25620), [\#25615](https://github.com/facebook/react/pull/25615), [\#25922](https://github.com/facebook/react/pull/25922), [\#25641](https://github.com/facebook/react/pull/25641), [\#25634](https://github.com/facebook/react/pull/25634), [\#26232](https://github.com/facebook/react/pull/26232), [\#26536](https://github.com/facebook/react/pull/26535), [\#26739](https://github.com/facebook/react/pull/26739), [\#28233](https://github.com/facebook/react/pull/28233) by [@acdlite](https://github.com/acdlite), [@MofeiZ](https://github.com/mofeiZ), [@sebmarkbage](https://github.com/sebmarkbage), [@sophiebits](https://github.com/sophiebits), [@eps1lon](https://github.com/eps1lon), and [@hansottowirtz](https://github.com/hansottowirtz)) * Add `useOptimistic()` hook to display mutated state optimistically during an async mutation ([\#26740](https://github.com/facebook/react/pull/26740), [\#26772](https://github.com/facebook/react/pull/26772), [\#27277](https://github.com/facebook/react/pull/27277), [\#27453](https://github.com/facebook/react/pull/27453), [\#27454](https://github.com/facebook/react/pull/27454), [\#27936](https://github.com/facebook/react/pull/27936) by [@acdlite](https://github.com/acdlite)) * Added an `initialValue` argument to `useDeferredValue()` hook ([\#27500](https://github.com/facebook/react/pull/27500), [\#27509](https://github.com/facebook/react/pull/27509), [\#27512](https://github.com/facebook/react/pull/27512), [\#27888](https://github.com/facebook/react/pull/27888), [\#27550](https://github.com/facebook/react/pull/27550) by [@acdlite](https://github.com/acdlite)) * Support refs as props, warn on `element.ref` access ([\#28348](https://github.com/facebook/react/pull/28348), [\#28464](https://github.com/facebook/react/pull/28464), [\#28731](https://github.com/facebook/react/pull/28731) by [@acdlite](https://github.com/acdlite)) * Support Custom Elements ([\#22184](https://github.com/facebook/react/pull/22184), [\#26524](https://github.com/facebook/react/pull/26524), [\#26523](https://github.com/facebook/react/pull/26523), [\#27511](https://github.com/facebook/react/pull/27511), [\#24541](https://github.com/facebook/react/pull/24541) by [@josepharhar](https://github.com/josepharhar), [@sebmarkbage](https://github.com/sebmarkbage), [@gnoff](https://github.com/gnoff) and [@eps1lon](https://github.com/eps1lon)) * Add ref cleanup function ([\#25686](https://github.com/facebook/react/pull/25686), [\#28883](https://github.com/facebook/react/pull/28883), [\#28910](https://github.com/facebook/react/pull/28910) by [@sammy-SC](https://github.com/sammy-SC), [@jackpope](https://github.com/jackpope), and [@kassens](https://github.com/kassens)) * Sibling pre-rendering replaced by sibling pre-warming ([\#26380](https://github.com/facebook/react/pull/26380), [\#26549](https://github.com/facebook/react/pull/26549), [\#30761](https://github.com/facebook/react/pull/30761), [\#30800](https://github.com/facebook/react/pull/30800), [\#30762](https://github.com/facebook/react/pull/30762), [\#30879](https://github.com/facebook/react/pull/30879), [\#30934](https://github.com/facebook/react/pull/30934), [\#30952](https://github.com/facebook/react/pull/30952), [\#31056](https://github.com/facebook/react/pull/31056), [\#31452](https://github.com/facebook/react/pull/31452) by [@sammy-SC](https://github.com/sammy-SC), [@acdlite](https://github.com/acdlite), [@gnoff](https://github.com/gnoff), [@jackpope](https://github.com/jackpope), [@rickhanlonii](https://github.com/rickhanlonii)) * Don’t rethrow errors at the root ([\#28627](https://github.com/facebook/react/pull/28627), [\#28641](https://github.com/facebook/react/pull/28641) by [@sebmarkbage](https://github.com/sebmarkbage)) * Batch sync discrete, continuous, and default lanes ([\#25700](https://github.com/facebook/react/pull/25700) by [@tyao1](https://github.com/tyao1)) * Switch `<Context>` to mean `<Context.Provider>` ([\#28226](https://github.com/facebook/react/pull/28226) by [@gaearon](https://github.com/gaearon)) * Changes to *StrictMode* * Handle `info`, `group`, and `groupCollapsed` in *StrictMode* logging ([\#25172](https://github.com/facebook/react/pull/25172) by [@timneutkens](https://github.com/timneutkens)) * Refs are now attached/detached/attached in *StrictMode* ([\#25049](https://github.com/facebook/react/pull/25049) by [@sammy-SC](https://github.com/sammy-SC)) * Fix `useSyncExternalStore()` hydration in *StrictMode* ([\#26791](https://github.com/facebook/react/pull/26791) by [@sophiebits](https://github.com/sophiebits)) * Always trigger `componentWillUnmount()` in *StrictMode* ([\#26842](https://github.com/facebook/react/pull/26842) by [@tyao1](https://github.com/tyao1)) * Restore double invoking `useState()` and `useReducer()` initializer functions in *StrictMode* ([\#28248](https://github.com/facebook/react/pull/28248) by [@eps1lon](https://github.com/eps1lon)) * Reuse memoized result from first pass ([\#25583](https://github.com/facebook/react/pull/25583) by [@acdlite](https://github.com/acdlite)) * Fix `useId()` in *StrictMode* ([\#25713](https://github.com/facebook/react/pull/25713) by [@gnoff](https://github.com/gnoff)) * Add component name to *StrictMode* error messages ([\#25718](https://github.com/facebook/react/pull/25718) by [@sammy-SC](https://github.com/sammy-SC)) * Add support for rendering BigInt ([\#24580](https://github.com/facebook/react/pull/24580) by [@eps1lon](https://github.com/eps1lon)) * `act()` no longer checks `shouldYield` which can be inaccurate in test environments ([\#26317](https://github.com/facebook/react/pull/26317) by [@acdlite](https://github.com/acdlite)) * Warn when keys are spread with props ([\#25697](https://github.com/facebook/react/pull/25697), [\#26080](https://github.com/facebook/react/pull/26080) by [@sebmarkbage](https://github.com/sebmarkbage) and [@kassens](https://github.com/kassens)) * Generate sourcemaps for production build artifacts ([\#26446](https://github.com/facebook/react/pull/26446) by [@markerikson](https://github.com/markerikson)) * Improve stack diffing algorithm ([\#27132](https://github.com/facebook/react/pull/27132) by [@KarimP](https://github.com/KarimP)) * Suspense throttling lowered from 500ms to 300ms ([\#26803](https://github.com/facebook/react/pull/26803) by [@acdlite](https://github.com/acdlite)) * Lazily propagate context changes ([\#20890](https://github.com/facebook/react/pull/20890) by [@acdlite](https://github.com/acdlite) and [@gnoff](https://github.com/gnoff)) * Immediately rerender pinged fiber ([\#25074](https://github.com/facebook/react/pull/25074) by [@acdlite](https://github.com/acdlite)) * Move update scheduling to microtask ([\#26512](https://github.com/facebook/react/pull/26512) by [@acdlite](https://github.com/acdlite)) * Consistently apply throttled retries ([\#26611](https://github.com/facebook/react/pull/26611), [\#26802](https://github.com/facebook/react/pull/26802) by [@acdlite](https://github.com/acdlite)) * Suspend Thenable/Lazy if it's used in React.Children ([\#28284](https://github.com/facebook/react/pull/28284) by [@sebmarkbage](https://github.com/sebmarkbage)) * Detect infinite update loops caused by render phase updates ([\#26625](https://github.com/facebook/react/pull/26625) by [@acdlite](https://github.com/acdlite)) * Update conditional hooks warning ([\#29626](https://github.com/facebook/react/pull/29626) by [@sophiebits](https://github.com/sophiebits)) * Update error URLs to go to new docs ([\#27240](https://github.com/facebook/react/pull/27240) by [@rickhanlonii](https://github.com/rickhanlonii)) * Rename the `react.element` symbol to `react.transitional.element` ([\#28813](https://github.com/facebook/react/pull/28813) by [@sebmarkbage](https://github.com/sebmarkbage)) * Fix crash when suspending in shell during `useSyncExternalStore()` re-render ([\#27199](https://github.com/facebook/react/pull/27199) by [@acdlite](https://github.com/acdlite)) * Fix incorrect “detected multiple renderers" error in tests ([\#22797](https://github.com/facebook/react/pull/22797) by [@eps1lon](https://github.com/eps1lon)) * Fix bug where effect cleanup may be called twice after bailout ([\#26561](https://github.com/facebook/react/pull/26561) by [@acdlite](https://github.com/acdlite)) * Fix suspending in shell during discrete update ([\#25495](https://github.com/facebook/react/pull/25495) by [@acdlite](https://github.com/acdlite)) * Fix memory leak after repeated setState bailouts ([\#25309](https://github.com/facebook/react/pull/25309) by [@acdlite](https://github.com/acdlite)) * Fix `useSyncExternalStore()` dropped update when state is dispatched in render phase ([\#25578](https://github.com/facebook/react/pull/25578) by [@pandaiolo](https://github.com/pandaiolo)) * Fix logging when rendering a lazy fragment ([\#30372](https://github.com/facebook/react/pull/30372) by [@tom-sherman](https://github.com/tom-sherman)) * Remove string refs ([\#25383](https://github.com/facebook/react/pull/25383), [\#28322](https://github.com/facebook/react/pull/28322) by [@eps1lon](https://github.com/eps1lon) and [@acdlite](https://github.com/acdlite)) * Remove Legacy Context (\#30319 by [@kassens](https://github.com/kassens)) * Remove `RefreshRuntime.findAffectedHostInstances` ([\#30538](https://github.com/facebook/react/pull/30538) by [@gaearon](https://github.com/gaearon)) * Remove client caching from `cache()` API ([\#27977](https://github.com/facebook/react/pull/27977), [\#28250](https://github.com/facebook/react/pull/28250) by [@acdlite](https://github.com/acdlite) and [@gnoff](https://github.com/gnoff)) * Remove `propTypes` ([\#28324](https://github.com/facebook/react/pull/28324), [\#28326](https://github.com/facebook/react/pull/28326) by [@gaearon](https://github.com/gaearon)) * Remove `defaultProps` support, except for classes ([\#28733](https://github.com/facebook/react/pull/28733) by [@acdlite](https://github.com/acdlite)) * Remove UMD builds ([\#28735](https://github.com/facebook/react/pull/28735) by [@gnoff](https://github.com/gnoff)) * Remove delay for non-transition updates ([\#26597](https://github.com/facebook/react/pull/26597) by [@acdlite](https://github.com/acdlite)) * Remove `createFactory` ([\#27798](https://github.com/facebook/react/pull/27798) by [@kassens](https://github.com/kassens)) == React DOM * Adds Form Actions to handle form submission ([\#26379](https://github.com/facebook/react/pull/26379), [\#26674](https://github.com/facebook/react/pull/26674), [\#26689](https://github.com/facebook/react/pull/26689), [\#26708](https://github.com/facebook/react/pull/26708), [\#26714](https://github.com/facebook/react/pull/26714), [\#26735](https://github.com/facebook/react/pull/26735), [\#26846](https://github.com/facebook/react/pull/26846), [\#27358](https://github.com/facebook/react/pull/27358), [\#28056](https://github.com/facebook/react/pull/28056) by [@sebmarkbage](https://github.com/sebmarkbage), [@acdlite](https://github.com/acdlite), and [@jupapios](https://github.com/jupapios)) * Add `useFormStatus()` hook to provide status information of the last form submission ([\#26719](https://github.com/facebook/react/pull/26719), [\#26722](https://github.com/facebook/react/pull/26722), [\#26788](https://github.com/facebook/react/pull/26788), [\#29019](https://github.com/facebook/react/pull/29019), [\#28728](https://github.com/facebook/react/pull/28728), [\#28413](https://github.com/facebook/react/pull/28413) by [@acdlite](https://github.com/acdlite) and [@eps1lon](https://github.com/eps1lon)) * Support for Document Metadata. Adds `preinit`, `preinitModule`, `preconnect`, `prefetchDNS`, `preload`, and `preloadModule` APIs. * [\#25060](https://github.com/facebook/react/pull/25060), [\#25243](https://github.com/facebook/react/pull/25243), [\#25388](https://github.com/facebook/react/pull/25388), [\#25432](https://github.com/facebook/react/pull/25432), [\#25436](https://github.com/facebook/react/pull/25436), [\#25426](https://github.com/facebook/react/pull/25426), [\#25500](https://github.com/facebook/react/pull/25500), [\#25480](https://github.com/facebook/react/pull/25480), [\#25508](https://github.com/facebook/react/pull/25508), [\#25515](https://github.com/facebook/react/pull/25515), [\#25514](https://github.com/facebook/react/pull/25514), [\#25532](https://github.com/facebook/react/pull/25532), [\#25536](https://github.com/facebook/react/pull/25536), [\#25534](https://github.com/facebook/react/pull/25534), [\#25546](https://github.com/facebook/react/pull/25546), [\#25559](https://github.com/facebook/react/pull/25559), [\#25569](https://github.com/facebook/react/pull/25569), [\#25599](https://github.com/facebook/react/pull/25599), [\#25689](https://github.com/facebook/react/pull/25689), [\#26106](https://github.com/facebook/react/pull/26106), [\#26152](https://github.com/facebook/react/pull/26152), [\#26239](https://github.com/facebook/react/pull/26239), [\#26237](https://github.com/facebook/react/pull/26237), [\#26280](https://github.com/facebook/react/pull/26280), [\#26154](https://github.com/facebook/react/pull/26154), [\#26256](https://github.com/facebook/react/pull/26256), [\#26353](https://github.com/facebook/react/pull/26353), [\#26427](https://github.com/facebook/react/pull/26427), [\#26450](https://github.com/facebook/react/pull/26450), [\#26502](https://github.com/facebook/react/pull/26502), [\#26514](https://github.com/facebook/react/pull/26514), [\#26531](https://github.com/facebook/react/pull/26531), [\#26532](https://github.com/facebook/react/pull/26532), [\#26557](https://github.com/facebook/react/pull/26557), [\#26871](https://github.com/facebook/react/pull/26871), [\#26881](https://github.com/facebook/react/pull/26881), [\#26877](https://github.com/facebook/react/pull/26877), [\#26873](https://github.com/facebook/react/pull/26873), [\#26880](https://github.com/facebook/react/pull/26880), [\#26942](https://github.com/facebook/react/pull/26942), [\#26938](https://github.com/facebook/react/pull/26938), [\#26940](https://github.com/facebook/react/pull/26940), [\#26939](https://github.com/facebook/react/pull/26939), [\#27030](https://github.com/facebook/react/pull/27030), [\#27201](https://github.com/facebook/react/pull/27201), [\#27212](https://github.com/facebook/react/pull/27212), [\#27217](https://github.com/facebook/react/pull/27217), [\#27218](https://github.com/facebook/react/pull/27218), [\#27220](https://github.com/facebook/react/pull/27220), [\#27224](https://github.com/facebook/react/pull/27224), [\#27223](https://github.com/facebook/react/pull/27223), [\#27269](https://github.com/facebook/react/pull/27269), [\#27260](https://github.com/facebook/react/pull/27260), [\#27347](https://github.com/facebook/react/pull/27347), [\#27346](https://github.com/facebook/react/pull/27346), [\#27361](https://github.com/facebook/react/pull/27361), [\#27400](https://github.com/facebook/react/pull/27400), [\#27541](https://github.com/facebook/react/pull/27541), [\#27610](https://github.com/facebook/react/pull/27610), [\#28110](https://github.com/facebook/react/pull/28110), [\#29693](https://github.com/facebook/react/pull/29693), [\#29732](https://github.com/facebook/react/pull/29732), [\#29811](https://github.com/facebook/react/pull/29811), [\#27586](https://github.com/facebook/react/pull/27586), [\#28069](https://github.com/facebook/react/pull/28069) by [@gnoff](https://github.com/gnoff), [@sebmarkbage](https://github.com/sebmarkbage), [@acdlite](https://github.com/acdlite), [@kassens](https://github.com/kassens), [@sokra](https://github.com/sokra), [@sweetliquid](https://github.com/sweetliquid) * Add `fetchPriority` to `<img>` and `<link>` ([\#25927](https://github.com/facebook/react/pull/25927) by [@styfle](https://github.com/styfle)) * Add support for SVG `transformOrigin` prop ([\#26130](https://github.com/facebook/react/pull/26130) by [@arav-ind](https://github.com/arav-ind)) * Add support for `onScrollEnd` event ([\#26789](https://github.com/facebook/react/pull/26789) by [@devongovett](https://github.com/devongovett)) * Allow `<hr>` as child of `<select>` ([\#27632](https://github.com/facebook/react/pull/27632) by [@SouSingh](https://github.com/SouSingh)) * Add support for Popover API ([\#27981](https://github.com/facebook/react/pull/27981) by [@eps1lon](https://github.com/eps1lon)) * Add support for `inert` ([\#24730](https://github.com/facebook/react/pull/24730) by [@eps1lon](https://github.com/eps1lon)) * Add support for `imageSizes` and `imageSrcSet` ([\#22550](https://github.com/facebook/react/pull/22550) by [@eps1lon](https://github.com/eps1lon)) * Synchronously flush transitions in popstate events ([\#26025](https://github.com/facebook/react/pull/26025), [\#27559](https://github.com/facebook/react/pull/27559), [\#27505](https://github.com/facebook/react/pull/27505), [\#30759](https://github.com/facebook/react/pull/30759) by [@tyao1](https://github.com/tyao1) and [@acdlite](https://github.com/acdlite)) * `flushSync` exhausts queue even if something throws ([\#26366](https://github.com/facebook/react/pull/26366) by [@acdlite](https://github.com/acdlite)) * Throw error if `react` and `react-dom` versions don’t match ([\#29236](https://github.com/facebook/react/pull/29236) by [@acdlite](https://github.com/acdlite)) * Ensure `srcset` and `src` are assigned last on `<img>` instances ([\#30340](https://github.com/facebook/react/pull/30340) by [@gnoff](https://github.com/gnoff)) * Javascript URLs are replaced with functions that throw errors ([\#26507](https://github.com/facebook/react/pull/26507), [\#29808](https://github.com/facebook/react/pull/29808) by [@sebmarkbage](https://github.com/sebmarkbage) and [@kassens](https://github.com/kassens)) * Treat toggle and beforetoggle as discrete events ([\#29176](https://github.com/facebook/react/pull/29176) by [@eps1lon](https://github.com/eps1lon)) * Filter out empty `src` and `href` attributes (unless for `<a href=”” />`) ([\#18513](https://github.com/facebook/react/pull/18513), [\#28124](https://github.com/facebook/react/pull/28124) by [@bvaughn](https://github.com/bvaughn) and [@eps1lon](https://github.com/eps1lon)) * Fix unitless `scale` style property ([\#25601](https://github.com/facebook/react/pull/25601) by [@JonnyBurger](https://github.com/JonnyBurger)) * Fix `onChange` error message for controlled `<select>` ([\#27740](https://github.com/facebook/react/pull/27740) by [@Biki-das](https://github.com/Biki-das)) * Fix focus restore in child windows after element reorder ([\#30951](https://github.com/facebook/react/pull/30951) by [@ling1726](https://github.com/ling1726)) * Remove `render`, `hydrate`, `findDOMNode`, `unmountComponentAtNode`, `unstable_createEventHandle`, `unstable_renderSubtreeIntoContainer`, and `unstable_runWithPriority`. Move `createRoot` and `hydrateRoot` to `react-dom/client`. ([\#28271](https://github.com/facebook/react/pull/28271) by [@gnoff](https://github.com/gnoff)) * Remove `test-utils` ([\#28541](https://github.com/facebook/react/pull/28541) by [@eps1lon](https://github.com/eps1lon)) * Remove `unstable_flushControlled` ([\#26397](https://github.com/facebook/react/pull/26397) by [@kassens](https://github.com/kassens)) * Remove legacy mode ([\#28468](https://github.com/facebook/react/pull/28468) by [@gnoff](https://github.com/gnoff)) * Remove `renderToStaticNodeStream()` ([\#28873](https://github.com/facebook/react/pull/28873) by @gnoff) * Remove `unstable_renderSubtreeIntoContainer` ([\#29771](https://github.com/facebook/react/pull/29771) by [@kassens](https://github.com/kassens)) == React DOM Server * Stable release of React Server Components ([Many, many PRs](https://github.com/facebook/react/pulls?q=is%3Apr+is%3Aclosed+%5BFlight%5D+in%3Atitle+created%3A%3C2024-12-01+) by [@sebmarkbage](https://github.com/sebmarkbage), [@acdlite](https://github.com/acdlite), [@gnoff](https://github.com/gnoff), [@sammy-SC](https://github.com/sammy-SC), [@gaearon](https://github.com/gaearon), [@sophiebits](https://github.com/sophiebits), [@unstubbable](https://github.com/unstubbable), [@lubieowoce](https://github.com/lubieowoce)) * Support Server Actions ([\#26124](https://github.com/facebook/react/pull/26124), [\#26632](https://github.com/facebook/react/pull/26632), [\#27459](https://github.com/facebook/react/pull/27459) by [@sebmarkbage](https://github.com/sebmarkbage) and [@acdlite](https://github.com/acdlite)) * Changes to SSR * Add external runtime which bootstraps hydration on the client for binary transparency ([\#25437](https://github.com/facebook/react/pull/25437), [\#26169](https://github.com/facebook/react/pull/26169), [\#25499](https://github.com/facebook/react/pull/25499) by [@MofeiZ](https://github.com/mofeiZ) and [@acdlite](https://github.com/acdlite)) * Support subresource integrity for `bootstrapScripts` and `bootstrapModules` ([\#25104](https://github.com/facebook/react/pull/25104) by [@gnoff](https://github.com/gnoff)) * Fix null bytes written at text chunk boundaries ([\#26228](https://github.com/facebook/react/pull/26228) by [@sophiebits](https://github.com/sophiebits)) * Fix logic around attribute serialization ([\#26526](https://github.com/facebook/react/pull/26526) by [@gnoff](https://github.com/gnoff)) * Fix precomputed chunk cleared on Node 18 ([\#25645](https://github.com/facebook/react/pull/25645) by [@feedthejim](https://github.com/feedthejim)) * Optimize end tag chunks ([\#27522](https://github.com/facebook/react/pull/27522) by [@yujunjung](https://github.com/yujunjung)) * Gracefully handle suspending in DOM configs ([\#26768](https://github.com/facebook/react/pull/26768) by [@sebmarkbage](https://github.com/sebmarkbage)) * Check for nullish values on ReactCustomFormAction ([\#26770](https://github.com/facebook/react/pull/26770) by [@sebmarkbage](https://github.com/sebmarkbage)) * Preload `bootstrapModules`, `bootstrapScripts`, and update priority queue ([\#26754](https://github.com/facebook/react/pull/26754), [\#26753](https://github.com/facebook/react/pull/26753), [\#27190](https://github.com/facebook/react/pull/27190), [\#27189](https://github.com/facebook/react/pull/27189) by [@gnoff](https://github.com/gnoff)) * Client render the nearest child or parent suspense boundary if replay errors or is aborted ([\#27386](https://github.com/facebook/react/pull/27386) by [@sebmarkbage](https://github.com/sebmarkbage)) * Don't bail out of flushing if we still have pending root tasks ([\#27385](https://github.com/facebook/react/pull/27385) by [@sebmarkbage](https://github.com/sebmarkbage)) * Ensure Resumable State is Serializable ([\#27388](https://github.com/facebook/react/pull/27388) by [@sebmarkbage](https://github.com/sebmarkbage)) * Remove extra render pass when reverting to client render ([\#26445](https://github.com/facebook/react/pull/26445) by [@acdlite](https://github.com/acdlite)) * Fix unwinding context during selective hydration ([\#25876](https://github.com/facebook/react/pull/25876) by [@tyao1](https://github.com/tyao1)) * Stop flowing and then abort if a stream is cancelled ([\#27405](https://github.com/facebook/react/pull/27405) by [@sebmarkbage](https://github.com/sebmarkbage)) * Pass cancellation reason to abort ([\#27536](https://github.com/facebook/react/pull/27536) by [@sebmarkbage](https://github.com/sebmarkbage)) * Add `onHeaders` entrypoint option ([\#27641](https://github.com/facebook/react/pull/27641), [\#27712](https://github.com/facebook/react/pull/27712) by [@gnoff](https://github.com/gnoff)) * Escape `<style>` and `<script>` textContent to enable rendering inner content without dangerouslySetInnerHTML ([\#28870](https://github.com/facebook/react/pull/28870), [\#28871](https://github.com/facebook/react/pull/28871) by [@gnoff](https://github.com/gnoff)) * Fallback to client replaying actions for Blob serialization ([\#28987](https://github.com/facebook/react/pull/28987) by [@sebmarkbage](https://github.com/sebmarkbage)) * Render Suspense fallback if boundary contains new stylesheet during sync update ([\#28965](https://github.com/facebook/react/pull/28965) by [@gnoff](https://github.com/gnoff)) * Fix header length tracking (\#30327 by [@gnoff](https://github.com/gnoff)) * Use `srcset` to trigger load event on mount (\#30351 by [@gnoff](https://github.com/gnoff)) * Don't perform work when closing stream (\#30497 by [@gnoff](https://github.com/gnoff)) * Allow aborting during render (\#30488, [\#30730](https://github.com/facebook/react/pull/30730) by [@gnoff](https://github.com/gnoff)) * Start initial work immediately (\#31079 by [@gnoff](https://github.com/gnoff)) * A transition flowing into a dehydrated boundary no longer suspends when showing fallback ([\#27230](https://github.com/facebook/react/pull/27230) by [@acdlite](https://github.com/acdlite)) * Fix selective hydration triggers false update loop error ([\#27439](https://github.com/facebook/react/pull/27439) by [@acdlite](https://github.com/acdlite)) * Warn for Child Iterator of all types but allow Generator Components ([\#28853](https://github.com/facebook/react/pull/28853) by [@sebmarkbage](https://github.com/sebmarkbage)) * Include regular stack trace in serialized errors ([\#28684](https://github.com/facebook/react/pull/28684), [\#28738](https://github.com/facebook/react/pull/28738) by [@sebmarkbage](https://github.com/sebmarkbage)) * Aborting early no longer infinitely suspends ([\#24751](https://github.com/facebook/react/pull/24751) by [@sebmarkbage](https://github.com/sebmarkbage)) * Fix hydration warning suppression in text comparisons ([\#24784](https://github.com/facebook/react/pull/24784) by [@gnoff](https://github.com/gnoff)) * Changes to error handling in SSR * Add diffs to hydration warnings ([\#28502](https://github.com/facebook/react/pull/28502), [\#28512](https://github.com/facebook/react/pull/28512) by [@sebmarkbage](https://github.com/sebmarkbage)) * Make Error creation lazy ([\#24728](https://github.com/facebook/react/pull/24728) by [@sebmarkbage](https://github.com/sebmarkbage)) * Remove recoverable error when a sync update flows into a dehydrated boundary ([\#25692](https://github.com/facebook/react/pull/25692) by [@sebmarkbage](https://github.com/sebmarkbage)) * Don't "fix up" mismatched text content with suppressedHydrationWarning ([\#26391](https://github.com/facebook/react/pull/26391) by [@sebmarkbage](https://github.com/sebmarkbage)) * Fix component stacks in errors ([\#27456](https://github.com/facebook/react/pull/27456) by [@sebmarkbage](https://github.com/sebmarkbage)) * Add component stacks to `onError` ([\#27761](https://github.com/facebook/react/pull/27761), [\#27850](https://github.com/facebook/react/pull/27850) by [@gnoff](https://github.com/gnoff) and [@sebmarkbage](https://github.com/sebmarkbage)) * Throw hydration mismatch errors once ([\#28502](https://github.com/facebook/react/pull/28502) by [@sebmarkbage](https://github.com/sebmarkbage)) * Add Bun streaming server renderer ([\#25597](https://github.com/facebook/react/pull/25597) by [@colinhacks](https://github.com/colinhacks)) * Add nonce support to bootstrap scripts ([\#26738](https://github.com/facebook/react/pull/26738) by [@danieltott](https://github.com/danieltott)) * Add `crossorigin` support to bootstrap scripts ([\#26844](https://github.com/facebook/react/pull/26844) by [@HenriqueLimas](https://github.com/HenriqueLimas)) * Support `nonce` and `fetchpriority` in preload links ([\#26826](https://github.com/facebook/react/pull/26826) by [@liuyenwei](https://github.com/liuyenwei)) * Add `referrerPolicy` to `ReactDOM.preload()` ([\#27096](https://github.com/facebook/react/pull/27096) by [@styfle](https://github.com/styfle)) * Add server condition for `react/jsx-dev-runtime` ([\#28921](https://github.com/facebook/react/pull/28921) by [@himself65](https://github.com/himself65)) * Export version ([\#29596](https://github.com/facebook/react/pull/29596) by [@unstubbable](https://github.com/unstubbable)) * Rename the secret export of Client and Server internals ([\#28786](https://github.com/facebook/react/pull/28786), [\#28789](https://github.com/facebook/react/pull/28789) by [@sebmarkbage](https://github.com/sebmarkbage)) * Remove layout effect warning on server ([\#26395](https://github.com/facebook/react/pull/26395) by [@rickhanlonii](https://github.com/rickhanlonii)) * Remove `errorInfo.digest` from `onRecoverableError` ([\#28222](https://github.com/facebook/react/pull/28222) by [@gnoff](https://github.com/gnoff)) == ReactTestRenderer * Add deprecation error to `react-test-renderer` on web ([\#27903](https://github.com/facebook/react/pull/27903), [\#28904](https://github.com/facebook/react/pull/28904) by [@jackpope](https://github.com/jackpope) and [@acdlite](https://github.com/acdlite)) * Render with ConcurrentRoot on web ([\#28498](https://github.com/facebook/react/pull/28498) by [@jackpope](https://github.com/jackpope)) * Remove `react-test-renderer/shallow` export ([\#25475](https://github.com/facebook/react/pull/25475), [\#28497](https://github.com/facebook/react/pull/28497) by [@sebmarkbage](https://github.com/sebmarkbage) and [@jackpope](https://github.com/jackpope)) == React Reconciler * Enable suspending commits without blocking render ([\#26398](https://github.com/facebook/react/pull/26398), [\#26427](https://github.com/facebook/react/pull/26427) by [@acdlite](https://github.com/acdlite)) * Remove `prepareUpdate` ([\#26583](https://github.com/facebook/react/pull/26583), [\#27409](http://github.com/facebook/react/pull/27409) by [@sebmarkbage](https://github.com/sebmarkbage) and [@sophiebits](https://github.com/sophiebits)) == React-Is * Enable tree shaking ([\#27701](https://github.com/facebook/react/pull/27701) by [@markerikson](https://github.com/markerikson)) * Remove `isConcurrentMode` and `isAsyncMode` methods ([\#28224](https://github.com/facebook/react/pull/28224) by @gaearon) == useSyncExternalStore * Remove React internals access ([\#29868](https://github.com/facebook/react/pull/29868) by [@phryneas](https://github.com/phryneas)) * Fix stale selectors keeping previous store references ([\#25969](https://github.com/facebook/react/pull/25968) by [@jellevoost](https://github.com/jellevoost)) @types/react and @types/react-dom are published from DefinitelyTyped and have no changelog. Release notes: - https://github.com/facebook/react/blob/main/CHANGELOG.md - React 19 upgrade guide: https://react.dev/blog/2024/04/25/react-19-upgrade-guide
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
14 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
This PR updates the Rollup build pipeline to generate sourcemaps for production build artifacts like
react-dom.production.min.js.It requires the Rollup v3 changes that were just merged in #26442 .
Sourcemaps are currently only generated for build artifacts that are truly "production" - no sourcemaps will be generated for development, profiling, UMD, or
shouldStayReadableartifacts.The generated sourcemaps contain the bundled source contents right before that chunk was minified by Closure, and not the original source files like
react-reconciler/src/*. This better reflects the actual code that is running as part of the bundle, with all the feature flags and transformations that were applied to the source files to generate that bundle. The sourcemaps do still show comments and original function names, thus improving debuggability for production usage.Fixes #20186 .
This allows React users to actually debug a readable version of the React bundle in production scenarios. It also allows other tools like Replay to do a better job inspecting the React source when stepping through.
How did you test this change?
I've attached a set of production files + their sourcemaps here:
react-sourcemap-examples.zip
You can drag JS+sourcemap file pairs into https://evanw.github.io/source-map-visualization/ for viewing.
Examples:
react.production.min.js:react-dom.production.min.js:use-sync-external-store/with-selector.production.min.js: