facebook / flow

New Features:

• Improved IDE get definition behavior of imported names by jumping past module.exports = ... to the actual definition.

Library Definitions:

• Made offset an optional argument for the sized Buffer read/writes (thanks @isker!)

Misc:

• Removed deprecated blacklist/whitelist aliases for config options, use includes/excludes instead (see updated docs: for Types First and flowconfig options).

Likely to cause new Flow errors:

• $Keys<...> will no longer include non-own instance properties, matching the behavior of Object.keys.

Notable bug fixes:

• Fixed an incremental rechecking issue caused by the hashes of type destructors

Misc:

• Updated the type of cast and isValid to take in optional representation type for enums
• Added missing links to Medium articles from flow.org (thanks @jamesisaac)

New Features:

• Enable LSP support for autofix exports by default.
• Added a lint rule to ensure exports named default were exported with export default syntax.
• Enabled support for JSDoc in some LSP results.

Library Definitions:

• Add parameter to MediaStreamTrack.applyConstraints()

Parser:

• Fix parsing async arrow functions with multiple type parameters

Config:

• Remove types-first flag aliases prefixed with "experimental"
• Replace well_formed_exports.whitelist with well_formed_exports.includes

Misc:

• Improvements to editor in flow.org/try, including syntax highlighting
• Fix broken links in docs
• Standardized error suppression syntax, added ability to suppress errors based on error codes

Library Definitions:

• Add KD functions
• Add onended callback to OscillatorNode
• Make 3rd parameter of node.js symlinkSync optional

• Fixed an issue where changing .flowconfig or package.json and then running flow status would get stuck in a restart loop, if using lazy mode with Watchman and Mercurial.

• Allow indexers in exact object annotations
• Fixed type-at-pos in flow.org/try
• Improved language of LSP window/showStatus responses
• Improved control flow handing in logical expressions
• Allow applying utility types to opaque types in the defining module
• Added HeadersInit and signal to Fetch API (thanks @andretshurotshka!)
• Added replace method to DOMTokenList (thanks @w01fgang!)

Publishing of flow-bin v0.125.0 failed to include the binaries. Oops!

Likely to cause new Flow errors:

• Fixed signatures generated in types-first for classes with non-trivial expressions
  in their extends clauses, which were before treated like extending any.

New features:

• Types-first is no longer an experimental mode, but is now fully supported!

Notable bug fixes:

• Fixed a soundness bug that allowed refined property expressions to be treated as
  empty in some circumstances.

Misc:

• Added $FlowIssue and $FlowExpectedError as default suppression comments.
• Improved quality of AST and comment printing and layout.
• Improved quality of type printing for type-at-pos and friends.
• Added '.cjs' to default extensions list.

Parser:

• Fixed ranges of sequence and assignment expressions that contain grouping parentheses.
• Disallowed newline after type keyword in type aliases.

Library definitions:

• Added headers timeout to http & https server (thanks, @mattconde!)
• Added flushHeaders to http$ServerResponse (thanks, @gajus!)
• Changed thisArg parameter for array callback functions (e.g. map, reduce) to mixed.
• Added more precise typing for common cases of Array.flat.

Library Definitions:

• Add StorageEvent overloads.

Misc:

• Use textEdit in identifier completion item responses over the LSP, to avoid possible behavior differences with different LSP clients.
• Various improvements to the pretty-printer.
• A small improvement in completeness when handling the "not" operation in the presence of unions of literal types.
• Wrap the usage message to 100 chars.
• Fix a poorly-positioned error related to polymorphic function types.

Parser:

• Improved some parser error messages by treating the end of file as a valid end of object property.
• Updated ESTree output for import expressions to match the spec.

flow-dev-tools:

• Add the update-suppressions subcommand.