microsoft/TypeScript

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TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

Stars: 111k
Forks: 14.4k
Open beginner issues: 18
Indexed issues: 4.9k
Avg merge: 1d 19h
Merged PRs (30d): 117

Dominant language: Go
License: Apache-2.0
Last GitHub push: Sep 19, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted good first issue

Beginner friendly Everything

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4,855 open issues indexed

Reflect Metadata not supported for TC39 decorators Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/TypeScript#55788 · 9 comments · 19 reactions · Opened Sep 19, 2023
Valid filter predicates rejected after 5.2.2 upgrade #53489 Open

Needs Investigation

microsoft/TypeScript#55777 · 2 comments · 1 reaction · 1 assignee · Opened Sep 18, 2023
Control flow analysis for dependent parameters only works when checking against literals Open

Domain: check: Control Flow Help Wanted Possible Improvement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55766 · 2 comments · 2 reactions · Opened Sep 17, 2023
Limit the Amount of Intellisense Result Open

Needs Proposal Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#56775 · 2 comments · Opened Sep 16, 2023
When evaluating whether a generic is assignable to a generic, it depends on the type order. Open

Needs More Info

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55759 · 2 comments · Opened Sep 16, 2023
Recursive types can depend on presence and source location of unused type declaration Open

Needs Investigation

microsoft/TypeScript#55758 · 12 comments · 1 reaction · 1 assignee · Opened Sep 16, 2023
cannot redeclare block scoped variable postMessage() Open

Needs More Info

Difficulty 4/5 3-5 days Newbie friendliness 32/100

microsoft/TypeScript#55752 · 4 comments · Opened Sep 15, 2023
Use single-assignment variables for intermediate values needed in JS output for decorated classes Open

Needs Investigation

microsoft/TypeScript#55734 · 1 comment · 1 assignee · Opened Sep 13, 2023
Certain conditional types allow unsound assignments Open

Bug Cursed? Domain: Conditional Types Help Wanted

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/TypeScript#55733 · 6 comments · Opened Sep 13, 2023
API `getSemanticDiagnostics` reports wrong error for code extends interface in namespace Open

Needs More Info

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55729 · 5 comments · Opened Sep 13, 2023
Common property check isn't performed when the target has any index signature Open

Domain: check: Excess Property Checking Possible Improvement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55709 · 1 reaction · Opened Sep 11, 2023
Identities should report an error Open

Experimentation Needed Suggestion

microsoft/TypeScript#55699 · 6 comments · 1 assignee · Opened Sep 10, 2023
Display inlay hints with defining variables by destructuring assignment Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55692 · 3 comments · 1 reaction · Opened Sep 9, 2023
Feedback on Standard Decorators emit size Open

Discussion

Difficulty 5/5 Over a week Newbie friendliness 25/100

microsoft/TypeScript#55688 · 8 comments · Opened Sep 8, 2023
Add a recursion limit to improve stack overflow errors Open

Awaiting More Feedback Suggestion

Difficulty 5/5 Over a week Newbie friendliness 25/100

microsoft/TypeScript#55687 · 6 comments · Opened Sep 8, 2023
Capitalize does not work for characters which are 2 utf-16 code units Open

Awaiting More Feedback Suggestion

Difficulty 3/5 1-2 days Newbie friendliness 42/100

microsoft/TypeScript#55677 · 2 comments · Opened Sep 8, 2023
Instantiations of constrained generic signatures allow all assignments Open

Bug Domain: check: Variance Relationships

microsoft/TypeScript#55671 · 1 comment · 1 assignee · Opened Sep 7, 2023
Experimental decorators do not get access to the initial value when using auto-accessors Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55669 · 8 comments · 2 reactions · Opened Sep 7, 2023
`ReturnType` and `InstanceType` don't work for functions/constructors with `never` in their parameters Open

Domain: lib.d.ts Effort: Casual Experimentation Needed Help Wanted Suggestion

Difficulty 3/5 1-2 days Newbie friendliness 42/100

microsoft/TypeScript#55667 · 3 comments · 6 reactions · Opened Sep 7, 2023
discriminated union type narrow when destructuring object within desturct array Open

Experimentation Needed Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55664 · 4 comments · 1 reaction · Opened Sep 7, 2023
Intersected type variable with a recursive constraint fails to infer Open

Needs Proposal Suggestion

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/TypeScript#55645 · 4 comments · Opened Sep 6, 2023
Surprising excess property check with recursive generic constraint Open

Domain: check: Excess Property Checking Help Wanted Possible Improvement

Difficulty 4/5 3-5 days Newbie friendliness 42/100

microsoft/TypeScript#55644 · 5 comments · Opened Sep 6, 2023
Invalid recursive methods or functions Open

Needs Proposal Suggestion

Difficulty 5/5 Over a week Newbie friendliness 28/100

microsoft/TypeScript#55643 · 6 comments · 1 reaction · Opened Sep 6, 2023
Typescript has more trouble resolving circular class references when using mixins / through function invocations Open

Domain: check: Type Circularity Help Wanted Possible Improvement

Difficulty 5/5 Over a week Newbie friendliness 30/100

microsoft/TypeScript#55640 · Opened Sep 5, 2023
No type inferrence of callback arguments inside a tuple union type Open

Bug Domain: check: Type Inference Help Wanted

Difficulty 4/5 3-5 days Newbie friendliness 42/100

microsoft/TypeScript#55632 · 5 comments · Opened Sep 5, 2023
Incorrect conditional type evaluation on transformed function type expressions Open

Needs Investigation

microsoft/TypeScript#55587 · 1 comment · 1 assignee · Opened Aug 31, 2023
Resolve documentation for type aliases Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55572 · 2 reactions · Opened Aug 30, 2023
Module is present in declarations even though it is unused. Open

Bug Domain: Declaration Emit

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/TypeScript#55571 · Opened Aug 30, 2023
`in` operator narrowing (`key in obj`) doesn't work properly when key type is a string union Open

Domain: check: Control Flow Possible Improvement

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/TypeScript#55561 · 8 comments · 3 reactions · Opened Aug 29, 2023
Temp variable re-usage breaks JS when building into single file Open

Needs More Info

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/TypeScript#55560 · 10 comments · Opened Aug 29, 2023
When assigning a generic to a generic type prop, it is not evaluated like a set Open

Needs More Info

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55524 · 3 comments · Opened Aug 27, 2023
The Meta Type System — A Proposal Open

Awaiting More Feedback Suggestion

Difficulty 5/5 Over a week Newbie friendliness 25/100

microsoft/TypeScript#55521 · 7 comments · 41 reactions · Opened Aug 26, 2023
Inlay hints for type parameters on type arguments Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55591 · 9 comments · 8 reactions · Opened Aug 25, 2023
JS `Object.defineProperty` declaration can't define divergent accessors Open

Domain: JavaScript Experience Enhancement Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/TypeScript#55505 · Opened Aug 24, 2023
Incorrect error reported when using `class extends null` and re-opening interface Open

Bug Domain: classes Rescheduled

microsoft/TypeScript#55500 · 1 assignee · Opened Aug 24, 2023
Incorrect error message on invalid union type assignation Open

Experience Enhancement Help Wanted Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55465 · 8 comments · Opened Aug 22, 2023
Go-to-definition on interfaces shadowed by namespaces opens a selection dialog instead of going to the interface, when used as one. Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55593 · 6 comments · 4 reactions · Opened Aug 21, 2023
type gets widened on declaration emit when inferred in destructuring context Open

Bug Domain: Declaration Emit

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55439 · 4 comments · 3 reactions · Opened Aug 20, 2023
Unreachable returns badly break return type inference Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/TypeScript#55437 · 7 comments · 1 reaction · Opened Aug 20, 2023
Compiler API: allow retrieving Symbols for anonymous function and classes Open

In Discussion Suggestion

Difficulty 5/5 Over a week Newbie friendliness 30/100

microsoft/TypeScript#55433 · Opened Aug 19, 2023
Issue with 'this' Parameter and JSX Component Generics Open

Bug Domain: This-Typing Rescheduled

microsoft/TypeScript#55431 · 1 assignee · Opened Aug 18, 2023
Support per volume case sensitivity Open

Awaiting More Feedback Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/TypeScript#55427 · 8 comments · Opened Aug 18, 2023
Cannot await Thenable Open

Needs Investigation

microsoft/TypeScript#55408 · 9 comments · 3 reactions · 1 assignee · Opened Aug 17, 2023
Generic indexed access on a substitution type with an array constraint resolves incorrectly Open

Domain: Indexed Access Types Possible Improvement

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/TypeScript#55383 · 3 reactions · Opened Aug 15, 2023
Explicitly annotated unique symbols are widened in return positions Open

Domain: Literal Types Possible Improvement

Difficulty 3/5 1-2 days Newbie friendliness 38/100

microsoft/TypeScript#55361 · 5 comments · 3 reactions · Opened Aug 14, 2023
Better error message when a module declaration is not found, but a module augmentation is? Open

Experience Enhancement Help Wanted Suggestion

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/TypeScript#55347 · 2 comments · Opened Aug 13, 2023
Co-dependency of variables destructured from union types is lost unless used in control-flow statements Open

Domain: check: Control Flow Help Wanted Possible Improvement

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/TypeScript#55344 · 2 comments · 2 reactions · Opened Aug 12, 2023
Incorrectly reported `TS2322` error on array items after spread Open

Bug Domain: Error Messages Help Wanted

Difficulty 4/5 3-5 days Newbie friendliness 42/100

microsoft/TypeScript#55340 · 1 comment · Opened Aug 11, 2023
TypeScript can't infer correct type from while loop if while condition is given a promise Open

Domain: check: Control Flow Help Wanted Possible Improvement

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/TypeScript#55300 · 5 comments · Opened Aug 8, 2023
Allow `readonly` with `accessor` Open

Revisit Suggestion

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/TypeScript#55289 · 5 comments · 7 reactions · Opened Aug 7, 2023

microsoft/TypeScript

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