facebook/flow v0.204.0

on GitHub

Likely to cause new Flow errors:

• Some heap refinements might be invalidated more aggressively, when method calls appear in conditionals. This brings us closer to what happens in the case of the regular function call. (Example)
• Always error on the deprecated existential type *, it's just an alias for any

New Features:

• Experimental support for Mapped Types like {[k in keyof T]: ?T[k]}! (Example). Look out for a blog post, documentation and support in other tools in the near future. You can try mapped types in your project by setting the experimental.mapped_type=true flag in the options section of your flowconfig.

Notable bug fixes:

• Fix autocomplete for super members (e.g., super.|)
• Fix hover type of JSX attribute names
• Fix showing documentation in signature help for member expressions (e.g., o.m(|))
• Fix unused-promise lint false positives for logical and conditional expressions
• Fix spurious error in overloaded generic calls when a contextual type is available (Example)
• Properly remove the : with inferred predicates in flow-remove-types

Parser:

• Error on classes with static prototype fields
• Fix missing parse error for class constructors that are async, generators or accessors. The former two were previously type errors rather than syntax errors.

Library Definitions:

• Add NodeJS stream promises (thanks @moroine)