facebook/flow v0.112.0

on GitHub

Likely to cause new Flow errors:

• JSX expressions now use the new spread semantics added in v0.111.0
• Attempting to write to or update a read-only property using operator assignment is now a type error

New Features:

• New ambiguous-object-type lint warning against use of {} object types (prefer {||} or {...} instead, even when exact-by-default is enabled).
• Improved support for optional chaining

Notable bug fixes:

• Malformed type annotations no longer trigger the unclear-type lint error
• Builtin classes can no longer be extended

Misc:

• Improved performance for utility types and refinements in unions
• Various improvements to autocomplete and get-def IDE services
• Add useDeferredValue and useTransition to React library definitions
• Add bytesWritten funciton to library definition (thanks @farzonl)