facebook/flow v0.105.0

on GitHub

Likely to cause new Flow errors:

• Types for FileReader properties and methods are now more precise (e.g., some parameters typed
  any are now typed ProgressEvent; some properties now have null added to their types). Thanks, @nwoltman!

• The value type parameter V of $ReadOnlyMap and $ReadOnlyWeakMap is now covariant. Thanks, @goodmind!

• Types for the vm module in node.js are now more precise. Thanks, @goodmind!

• The deprecated $Enum<...> utility type has now been deleted. Use $Keys<...> instead.

• Indexing tuples with floats is no longer allowed.

New Features:

• Added support for React.Profiler (React v16.9+). Thanks, @bvaughn!

• Added a --types flag to flow graph dep-graph to output only "type" dependencies: the subset of
  imports that the types of a module's exports depends on. (Without the flag, we output "code"
  dependencies: the set of all imports of a module.)

• Preliminary support for automatically inserting annotations on a module's exports through
  LSP. Thanks to @akuhlens (summer intern with the Flow team)!

• Preliminary support for definite assignment checking of class instance properties. Thanks to
  @pzp1997 (summer intern with the Flow team)!

• Added an option to .flowconfig for exact-by-default objects.

Perf fixes:

• Fixed a non-termination issue with a recursive use of mapped types.
• Fixed an exponential-blowup issue with a combined use of spreads and unions.
• Fixed an exponential-blowup issue with recursive use of array spreads.

Misc:

• Fixed LSP init to say codeLens is not supported.
• Fixed lots of cases of bad error positioning, unblocking improvements to error suppressions and
  error streaming. Thanks to @mvcccccc (summer intern with the Flow team)!

Parser:

• Improved a bunch of "unexpected" parse errors, providing what was expected in the error message.
• Fixed a bug in parsing of params in function types.