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@facebook-github-bot facebook-github-bot released this Oct 2, 2019 · 102 commits to master since this release

Likely to cause new Flow errors:

  • Flow was previously not typechecking delete, but now does
  • Object.defineProperty and similar methods now adhere more closely to the spec
  • Allow defaults for properties that may not exist in React components

Notable bug fixes:

  • $NonMaybeType<mixed> no longer includes null and undefined (Thanks @goodmind)


  • Deprecated $Supertype and $Subtype utilities are now removed entirely
  • flow-upgrade should now use https over git (Thanks @lukeapage)
  • Autocomplete now fires on spaces in JSX
  • Better error messages when a value is used as a type


  • Reduced memory usage by using a more compact representation for code locations
  • Types-first should no longer check direct dependents of files where the signature has not changed

Library Definitions

  • Add a number of CSSOM interfaces + fix HTMLStyleElement.sheet type (Thanks @kof)
  • Add AsyncIterator to node.js (Thanks @goodmind)
  • Add undefined to prelude (Thanks @goodmind)
  • Add String.prototype.matchAll (Thanks @goodmind)
Assets 7
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