facebook/flow

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Adds static typing to JavaScript to improve developer productivity and code quality.

Stars: 22.3k
Forks: 1.9k
Open beginner issues: 0
Indexed issues: 510

Dominant language: Rust
License: MIT
Last GitHub push: Sep 15, 2026
Latest indexed: Sep 15, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: good first issue help wanted
PR merge metrics: No merged PRs in 30d

Open All

510 open issues indexed

Dynamic `typeof` test with union types outside do not carry into closure scope Open

facebook/flow#3369 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Add a JS generated by babel having Flow Comment to Libs Open

question

facebook/flow#3372 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
How to get the union of the specific fields of another union ? Open

facebook/flow#3373 · 2 comments · 2 reactions · 0 assignees · Indexed Sep 15, 2026
Intersection of union type cannot be assigned to that union type Open

facebook/flow#3376 · 0 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
[bug] Intersection with a tagged union unable to refine type Open

facebook/flow#3391 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Implement flow for decorators (method decorators) Open

ES2015+ feature request

facebook/flow#3405 · 10 comments · 49 reactions · 0 assignees · Indexed Sep 15, 2026
[Docs] Document module publishing Open

documentation

facebook/flow#3420 · 0 comments · 7 reactions · 0 assignees · Indexed Sep 15, 2026
Language Grammar Specification Open

question

facebook/flow#3429 · 1 comment · 12 reactions · 0 assignees · Indexed Sep 15, 2026
Flow do not find map property in Proxy<Array<any>> Open

bug

facebook/flow#3435 · 3 comments · 2 reactions · 0 assignees · Indexed Sep 15, 2026
Support for recursive type bounds Open

feature request

facebook/flow#3437 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Add more comprehensive documentation for arrow function types Open

facebook/flow#3447 · 1 comment · 2 reactions · 0 assignees · Indexed Sep 15, 2026
Imported key in computed property results in lack of error detection Open

facebook/flow#3454 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Disjoint unions types with Maps Open

facebook/flow#3466 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
event (lowercased) is not being type and declaration checked Open

facebook/flow#3481 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Warn about dead code Open

facebook/flow#3492 · 5 comments · 13 reactions · 0 assignees · Indexed Sep 15, 2026
Can't spread props with intersection-of-objects type Open

bug

facebook/flow#3504 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Comparators not checking enum validity Open

facebook/flow#3553 · 11 comments · 2 reactions · 0 assignees · Indexed Sep 15, 2026
Define function parameter types based on other parameters Open

facebook/flow#3638 · 3 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Flow throws in package's source, but doesn't throw in installed version of package Open

facebook/flow#3656 · 5 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Question: conventions for vendor libs Open

declarations question

facebook/flow#3671 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Questions: libdefs vs flow files (syntax, differences, etc.) Open

question

facebook/flow#3672 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Octal and binary numbers > 2^63-1 crash the parser Open

Accepting PRs Crash Effort: easy parsing

facebook/flow#3674 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Refinement of polymorphic type does not work Open

facebook/flow#3679 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Improce docs & examples for interfaces, modules, classes, etc. Open

Accepting PRs help wanted

facebook/flow#3682 · 3 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
module.name_mapper.extension: Not working for stub folder named "__mocks__" Open

facebook/flow#3687 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Premature incompatibily errors in generic classes definitions Open

bug

facebook/flow#3711 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Is it possible to scan all files in a directory without @flow? Open

feature request

facebook/flow#3728 · 4 comments · 25 reactions · 0 assignees · Indexed Sep 15, 2026
variable refinement of a union Open

facebook/flow#3731 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
import star as does not work Open

facebook/flow#3732 · 1 comment · 5 reactions · 0 assignees · Indexed Sep 15, 2026
Union type restrictions don't work when used within other objects Open

Typing: unions/intersections

facebook/flow#3749 · 4 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
Stack overflow error on tracking.js "face.js" file Open

facebook/flow#3774 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Unreachable code not well detected Open

facebook/flow#3793 · 0 comments · 4 reactions · 0 assignees · Indexed Sep 15, 2026
Strange behaviour when variable is inited with null Open

facebook/flow#3802 · 3 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
Do...while types not treated same as while types Open

facebook/flow#3810 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Investigate what to do with malformed characters Open

parsing

facebook/flow#3814 · 0 comments · 1 reaction · 1 assignee · Indexed Sep 15, 2026
\u unicode escapes in identifiers not supported Open

bug parsing

facebook/flow#3837 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Invalid converage about parametrized elements involving type any Open

facebook/flow#3860 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Warn when promises are used as value Open

feature request linter

facebook/flow#3862 · 10 comments · 3 reactions · 0 assignees · Indexed Sep 15, 2026
Checking initialization not working with module pattern literals Open

facebook/flow#3864 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
share type definitions among libs Open

facebook/flow#3883 · 6 comments · 7 reactions · 0 assignees · Indexed Sep 15, 2026
Intersecting types based on Generic types Open

facebook/flow#3884 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Catch name_mapper exceptions Open

Crash Effort: easy

facebook/flow#3889 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Correctly resolve a `node_module` inside .flowconfig Open

module resolution

facebook/flow#3893 · 2 comments · 8 reactions · 0 assignees · Indexed Sep 15, 2026
Flow error with destructuring assignment when there is an optional and unused parameter Open

destructuring

facebook/flow#3908 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Function from class to class Open

facebook/flow#3915 · 3 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Object destructuring breaks disjoint union type. Open

destructuring Typing: unions/intersections

facebook/flow#3932 · 4 comments · 5 reactions · 0 assignees · Indexed Sep 15, 2026
What is correct way to declare custom class factory? Open

facebook/flow#3934 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Support for lower type bounds Open

feature request

facebook/flow#3950 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Property not found on intersection type Open

facebook/flow#3952 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Getter and setter variances change depending on whether both are present Open

bug Typing: property variance

facebook/flow#3984 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026

facebook/flow

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