Suggestion Backlog Slog, 4/20/2016 #8228

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1. Ryan Cavanaugh (RyanCavanaugh)

   added

   Design NotesNotes from our design meetingsNotes from our design meetings

   on Apr 20, 2016
2. RyanCavanaugh commented on Apr 20, 2016

   

   Ryan Cavanaugh (RyanCavanaugh)

   on Apr 20, 2016

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   More actions

   Postponed to Monday
3. RyanCavanaugh commented on May 9, 2016

   

   Ryan Cavanaugh (RyanCavanaugh)

   on May 9, 2016

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   More actions

   • negating type constraints #7993 Negative type constraints
     • Ryan's 'workaround' is disgusting 😄
     • See if other scenarios appear
   • Better display representation for intersection types #7705 Better display of intersection types
     • Agree the proposed behavior is desirable
     • There are potentially some differences between T & U and its decomposed form?
       • We can't think of any
     • What do we do if one is an object type and one isn't?
       • Just do this for the anonymous types of the intersection
     • It's actually really hard and dangerous
       • Because anonymous types can be self-referentially recursive
       • Potential for a lot of runaway bugs
     • Close to Too Complex given the risk/reward tradeof
     • Accepting PRs but they need a giant test suite
   • Destructured parameter should not enforce presence / non-nullability from type annotation on a property that's default-initialized #7678 Destructured parameter should not enforce presence / non-nullability from type annotation on a property that's default-initialized
     • Sympathetic that this is annoying
     • Real problem is that there's no syntactic room in Component1 to put a type annotation on just propC
     • Axiom: Type annotations always win
     • 👎 Too Complex
   • Allow ArrayLike as a spread source #7596 Allow ArrayLike as a spread source
     • If we look for ArrayLike, this would work
       • Compat problem with ES6 and surrogate pairs on strings
     • Also enables other good behavior like DOM collections
     • Does anyone spread a string on purpose?
     • 👍 Accepting PRs and live with surrogate pair compat issue
   • Suggestion: readonly constructor parameters #7590 readonly constructor parameter properties
     • Why didn't this work before? Unsure (keyword soup fear?)
     • Committed for 2.0
     • 👍
   • Excess properties are not checked e.g. in callbacks #7547 Excess properties not checked in callbacks
     • Agree this is not the ideal behavior
     • Caused by widening the return type of function expressions
     • Looking at Don't widen return types of function expressions #241 trying to figure out its status
     • Why do we have this behavior today?
       • The types that go in to widen only come from checkExpression, which have a limited domain of non-circular types
       • So we'd need to modify the widening logic to handle self-referential recursive types
     • Confusing but workaround is simple (add a return type annotation to function expression)
     • If Don't widen return types of function expressions #241 keeps happening, address it
     • Too Complex but keep an eye on function expression return type widening
   • Suggestion: Implied Promise return type in async functions #7284 Implied Promise return type in async functions
     • Working as intended - Spooky action at a distance hinders readability
     • 👎
   • Allow super constrains for type parameters #7265 Allow super constraints for type parameters
     • Dupe JSX: a way to make all the properties of value-based elements optional #7004
   • JSX: a way to make all the properties of value-based elements optional #7004 A way to make all properties of value-based elements optional
     • Architectural/perf concerns about the amount of indirection this requires
       • e.g. what is the internal behavior of Optionalize<string> ?
       • Generics prevent assumptions here
       • Important is that union/intersection types are always top-level
     • Very large work item, but this appears in a lot of frameworks
       • e.g. potential to construct previously unconstructable things (e.g. union types which have sub-union types as members)
     • Think about it some more
   • More specific JSON parse reviver argument in lib.d.ts #6955 More specific reviver type in JSON#parse
     • Breaking change for people who got a contextual any and indexed into an array
       • Seems unlikely and fix is very simple
     • 👍
   • Readonly indexer and constructor usage: question #6781 Readonly indexer and constructor usage
     • What's the intent of a readonly index signature? Disagreement
     • What's the actual code? Need to understand the scenario better
   • Allow defining static index signature #6480 Allow defining static index signature
     • 👍 Accepting PRs, should be reasonably straightforward
   • Leak of noImplicitAny checking with private static property #6415 Leak of noImplicitAny checking with private static property
     • A type query should never generate an implicit any
     • 👍 but fix is that it should be illegal to use the typeof a private member to annotate a public member
   • Provide an official set of Coding Guidelines #878 Provide official coding guidelines
     • Nope
   • Partial classes  #563 Partial classes
     • Just sugar for interface A { methods; }, A.prototype.methods = ...
     • Allow property declarations and methods, but not property initializers (no way to emit)
     • Allow statics as well (including initializers, since we can emit those)
     • People are already sort of doing this already
     • Bikeshed partial keyword
       • extension class is the name C# would have called it but there isn't a clear "master" declaration like there is here
       • Confuse people by making it almost the same as C#, but not?
       • Or have a new keyword that we have to explain is 'close to' partial
       • Which will be preferable?
   • Special bottom type #3076 Special 'bottom' type
     • Out of time
   • Default generic type variables #2175 Default generic types
     • Out of time
4. Ryan Cavanaugh (RyanCavanaugh)

   closed this as completedon May 9, 2016
5. microsoft

   locked and limited conversation to collaborators on Jun 19, 2018