Suggestion Backlog Slog, 2/1/2016

[RyanCavanaugh]

On the docket

• Destructuring causes error for null/undefined properties #6784 - Destructuring a property of an optional property should be an error
• Add separate compiler option for generated declarations output directory. #6723 - Allow separate outDir for declaration files
• Const numbers that index into tuples do not produce the correct type #6678 - Use const initializer to resolve tuple type indexing
• Should not suggest "caller" in strict mode as it causes TypeError #6649 - Do not suggest caller in strict mode
• Make typings in package.json an array #6585 - Making typings in package.json an array
• Allow defining static index signature #6480 - Allow static index signatures in classes
• Using lookahead to detect generic JSX elements? #6395 - Provide a way of specifying type parameters in JSX tags
• empty return statement should be a compiler error when return type is specified #5916 - Disallow return; statements when a return type annotation exists
• Disallow empty binding patterns #5352 - Disallow empty binding patterns
• Support a 'declarationPath' option #6482 - Support a declarationPath option
• allow narrowing to any sub-type-expression in type guards #6544 - Allow narrowing to a constituent of an intersection type
• allow partially specified type arguments #6344 - Allow elided type arguments at call sites
• Proposal: Get the type of any expression with typeof #6606 - Apply typeof to arbitrary expressions

Stretch goals

• Why does { foo: T } not satisfy { [key:string]: T }? #6041 - Resolve the indexer mess
• More accurate typing of Object.assign and React component setState() #6613 - Better typing for React.setState

[RyanCavanaugh]

Notes

• Destructuring causes error for null/undefined properties #6784 - Destructuring a property of an optional property should be an error
  • Accepting PRs - a property destructuring must either be non-optional or have a default, otherwise a type error occurs. No change to emit.
• Add separate compiler option for generated declarations output directory. #6723 - Allow separate outDir for declaration files
  • Accepting PRs
• Const numbers that index into tuples do not produce the correct type #6678 - Use const initializer to resolve tuple type indexing
  • Allow computable expressions to initialize consts in .d.ts files (same as const enum initalizers)
  • And perform the "consts are the same as literals" step
  • And inline too under a flag
  • Accepting PRs
• Should not suggest "caller" in strict mode as it causes TypeError #6649 - Do not suggest caller in strict mode
  • Won't Fix
• Make typings in package.json an array #6585 - Making typings in package.json an array
  • Declined -- provide an index.d.ts full of reference tags
• Allow defining static index signature #6480 - Allow static index signatures in classes
  • Need more information on the scenario
• Using lookahead to detect generic JSX elements? #6395 - Provide a way of specifying type parameters in JSX tags
  • Accepting PRs
• empty return statement should be a compiler error when return type is specified #5916 - Disallow return; statements when a return type annotation exists
  • Put this under --noImplicitReturns flag
  • Accepting PRs
• Disallow empty binding patterns #5352 - Disallow empty binding patterns
  • Not an error in ES6, so not an error in TypeScript
• Support a 'declarationPath' option #6482 - Support a declarationPath option
  • Duplicate Add separate compiler option for generated declarations output directory. #6723
• allow narrowing to any sub-type-expression in type guards #6544 - Allow narrowing to a constituent of an intersection type
  • Type guard returns must be a subtype because they introduce new properties in their guarded expressions, not remove them
• allow partially specified type arguments #6344 - Allow elided type arguments at call sites
  • Too complex / confusing
• Proposal: Get the type of any expression with typeof #6606 - Apply typeof to arbitrary expressions
  • Allow f(), new f(), f.g, and f[string] or f[number]
  • Write down some implementation notes and see if anyone can tackle it
  • See how it turns out

Stretch goals

• More accurate typing of Object.assign and React component setState() #6613 - Better typing for React.setState
  • We'd need type operators to solve this, which is a huge work item
  • Workaround of specifying all-optionals in state definition isn't too bad
  • Doesn't solve many other use cases specifically
• Why does { foo: T } not satisfy { [key:string]: T }? #6041 - Resolve the indexer mess
  • Ran out of time