facebook/flow v0.147.0

on GitHub

Likely to cause new Flow errors:

• This release includes some significant architectural changes that fix bugs, improves performance, and may cause Flow to find more errors.
• Fixed a bug where "maybe types" like ?{c: number} did not properly error when used with utility types $PropertyType and $ElementType. null and undefined do not have properties nor elements.
• Object.prototype properties like toString and hasOwnProperty are no longer allowed to be accessed as global variables, which was previously allowed because window is an object.

New Features:

• Added Linux ARM64 support. A precompiled binary is provided, including through flow-bin.

Notable bug fixes:

• Improved the error message when getting properties on null and undefined
• Fixed running flow lsp on symlinked root directories

Misc:

• Removed support for @flow weak, which was a rarely-used mode in which missing annotations were treated as any. It is equivalent to suppressing any type errors that result from just using @flow. So to migrate, suppress the new errors and remove weak.
• Fixed a bug in which the built-in library definitions could be missing
• Fixed an obscure crash when using Watchman and Mercurial
• Added support for a flow.suggest.autoImports LSP setting to disable autoimport suggestions in autocomplete (currently requires autoimports=true to be enabled in .flowconfig)

Library definitions:

• Added support for node's assert strict mode (thanks @goodmind)
• Added support for .webp resources (thanks @TomasBarry)
• Added missing Brotli APIs to the zlib module (thanks @isker)
• Added missing methods to tty.WriteStream (thanks @reyronald)
• Changed process.exit to return empty

Parser:

• Fixed a regression in 0.146 where flow_parser.js defined some global variables