4 Pull requests merged by 4 people

• Preserve type parameter constraint in emitted mapped types while preserving their distributivity

  #54759 mergedMay 12, 2025

• Fix unwanted constant comparisons potentially causing bugs

  #61655 mergedMay 9, 2025

• Add configurable maximum hover length

  #61662 mergedMay 9, 2025

• DOM Update 2025-05-02

  #61647 mergedMay 7, 2025

4 Pull requests opened by 3 people

• Fix type variable s and cache inconsistencies

  #61668 openedMay 7, 2025

• Relate sources to base constraints of mapped type generic indexed accesses

  #61677 openedMay 8, 2025

• Compare optional property flag when comparing against discriminant properties under `exactOptionalPropertyTypes`

  #61682 openedMay 9, 2025

• Don't compare "missing" to `undefined` in `compareProperties` under `exactOptionalPropertyTypes`

  #61683 openedMay 9, 2025

23 Issues closed by 10 people

• Expanded function return type for certain mapped types in compiled output causes index access error

  #55049 closedMay 12, 2025

• Invalid declarations emitted when using ZodObject from zod as return type of generic function

  #54560 closedMay 12, 2025

• [ServerErrors][TypeScript] 5.9.0-dev.20250511 vs 5.8.3

  #61689 closedMay 12, 2025

• [ServerErrors][JavaScript] 5.9.0-dev.20250511 vs 5.8.3

  #61688 closedMay 12, 2025

• [NewErrors] 5.9.0-dev.20250511 vs 5.8.3

  #61687 closedMay 12, 2025

• TextNumber to boolean is error

  #61672 closedMay 11, 2025

• Typing issue with `extends` keyword

  #61673 closedMay 11, 2025

• Nullish coalescing operator does not understand cases where at least one operand is guaranteed to not be null, but not which one is not null

  #61670 closedMay 11, 2025

• Class method decorators reset the first field.

  #61665 closedMay 10, 2025

• Unwanted constant comparisons potentially causing bugs

  #61654 closedMay 9, 2025

• Setting noErrorTruncation to false truncates inferred type of variables/functions; which are not errors

  #26238 closedMay 9, 2025

• Add full type hover popup to VS Code commands

  #35601 closedMay 9, 2025

• Make object type const with a keyword

  #61681 closedMay 9, 2025

• Add an option not to use implicit any when I create an empty container (for example [], new Set() or new Map())

  #61638 closedMay 9, 2025

• TypeScript doesn't reverse-infer generic constraints from discriminated unions

  #61661 closedMay 9, 2025

• Cross-module inference issue: never-returning function doesn't prevent further type checking in async context

  #61649 closedMay 9, 2025

• Mishandling of generic parameter in Parameters

  #61675 closedMay 8, 2025

• TypeScript erroneously reports unused variable 'toDate'

  #61674 closedMay 8, 2025

• check

  #61669 closedMay 8, 2025

• Unexpected narrowing of optional fields via Object.entries

  #61650 closedMay 6, 2025

• [ServerErrors][TypeScript] 5.9.0-dev.20250504 vs 5.8.3

  #61658 closedMay 6, 2025

• [ServerErrors][JavaScript] 5.9.0-dev.20250504 vs 5.8.3

  #61657 closedMay 6, 2025

• [NewErrors] 5.9.0-dev.20250504 vs 5.8.3

  #61656 closedMay 6, 2025

15 Issues opened by 13 people

• This JSX tag's 'children' prop expects type 'string' which requires multiple children, but only a single child was provided

  #61692 openedMay 12, 2025

• The entries collection in observers should be non-empty

  #61691 openedMay 12, 2025

• Readonly methods and readonly types

  #61690 openedMay 12, 2025

• Circular Generic Type Transforms to New mutation Circular Generic Types

  #61686 openedMay 11, 2025

• Recursive Type Field Validation + Suggest, compile, fail over, Improve Transform of Circular Types Generic type hint Circular<type>

  #61685 openedMay 11, 2025

• Problem of losing "this" context in class method when casting to arrow function

  #61684 openedMay 11, 2025

• Generic TypedArray constructors have only one overload

  #61680 openedMay 9, 2025

• How to get the name of the codefix from getSupportedCodeFixes?

  #61679 openedMay 9, 2025

• With exactOptionalPropertyTypes enabled, assigning a union with missing literal properties is incorrectly allowed

  #61678 openedMay 9, 2025

• A contextually-typed signature coming from correlated union can't be assigned back to source of its contextual type

  #61676 openedMay 8, 2025

• public static fields without initializer are removed even with `useDefineForClassFields=true`

  #61671 openedMay 8, 2025

• Type variable and odd error

  #61667 openedMay 7, 2025

• Omit JSDoc type directives when emitting type declarations with documentation

  #61664 openedMay 6, 2025

• VS Code doesn't show autocomplete for Mongoose MongoDB operators (like $elemMatch, $match,$gte and ...) in JavaScript, while WebStorm does

  #61666 openedMay 6, 2025

• Tsserver never picks up a new file

  #61663 openedMay 6, 2025

62 Unresolved conversations

Sometimes conversations happen on old items that aren’t yet closed. Here is a list of all the Issues and Pull Requests with unresolved conversations.

• ServiceWorkerRegistration.Update() should return Promise<ServiceWorkerRegistration>

  #31502 commented onMay 6, 2025• 0 new comments

• Allow async functions to return union type T | Promise<T>

  #33595 commented onMay 6, 2025• 0 new comments

• tsconfig.json option removeComments removes comments from both declaration.d.ts and source .js files, it would be convenient to only remove comments from .js files.

  #45187 commented onMay 6, 2025• 0 new comments

• Autocomplete on extends keyof generic

  #28662 commented onMay 6, 2025• 0 new comments

• TypeScript 5.9 Iteration Plan

  #61648 commented onMay 6, 2025• 0 new comments

• Support cyclical type inference of self-referential data structures, when subject to some assignability constraints

  #61659 commented onMay 6, 2025• 0 new comments

• move to new file not working

  #61632 commented onMay 6, 2025• 0 new comments

• Proposal: Make base class expressions able to access class type parameters

  #36406 commented onMay 7, 2025• 0 new comments

• Allow base class expressions to reference class type parameters as long as the type param is not used on the static side of the resulting class

  #55972 commented onMay 7, 2025• 0 new comments

• source.organizeImports affects export object

  #61588 commented onMay 7, 2025• 0 new comments

• @deprecated strikethrough doesn't appear in many cases, such as JSX elements, const arrow functions, or properties.

  #39374 commented onMay 7, 2025• 0 new comments

• Intersection type in template literal is not reduced to its bare type

  #57918 commented onMay 8, 2025• 0 new comments

• `Element.getElementsByTagName` marked as deprecated

  #61264 commented onMay 8, 2025• 0 new comments

• tsc --init update 2024

  #58420 commented onMay 8, 2025• 0 new comments

• Support the `@private` JSDoc directive to exclude private APIs from emitted type declarations

  #61651 commented onMay 8, 2025• 0 new comments

• Excessive stack depth comparing types with TS 3.2

  #29112 commented onMay 8, 2025• 0 new comments

• Cannot Optionalize Class Getters

  #14417 commented onMay 8, 2025• 0 new comments

• Assigning window.location after 5.8.2 upgrade fails

  #61335 commented onMay 8, 2025• 0 new comments

• [Feature request]type level equal operator

  #48100 commented onMay 8, 2025• 0 new comments

• Support a @nonnull/@nonnullable JSDoc assertion comment

  #23405 commented onMay 8, 2025• 0 new comments

• Exact Types

  #12936 commented onMay 9, 2025• 0 new comments

• `// @ts-expect-deprecation` and `// @ts-expect-no-deprecation` support like `// @ts-expect-error`

  #50369 commented onMay 9, 2025• 0 new comments

• Invalid quick fix for function returning `Promise<unknown>` with `isolatedDeclarations`

  #61642 commented onMay 9, 2025• 0 new comments

• Support some non-structural (nominal) type matching

  #202 commented onMay 10, 2025• 0 new comments

• Confusing error message when there is an accidental circular reference in monorepo

  #61577 commented onMay 11, 2025• 0 new comments

• unique symbol + interface + mixin causes TS4058 ("but cannot be named")

  #57165 commented onMay 11, 2025• 0 new comments

• disallow comparing to null and undefined unless they are valid cases in strict null mode

  #11920 commented onMay 12, 2025• 0 new comments

• Support @class in JSDoc

  #12681 commented onMay 12, 2025• 0 new comments

• Error inferring types of promise function

  #17873 commented onMay 12, 2025• 0 new comments

• this any typed in some JS object literals

  #22058 commented onMay 12, 2025• 0 new comments

• Suggestion: Type annotations and interfaces for function declarations

  #22063 commented onMay 12, 2025• 0 new comments

• Allow extending types referenced through interfaces

  #31843 commented onMay 12, 2025• 0 new comments

• Support Intellisense for string/number literals in a widened union

  #33471 commented onMay 12, 2025• 0 new comments

• Implicit Symbol.iterator call in for..of loops / spread destructuring doesn't infer `this` generic type parameter

  #38388 commented onMay 12, 2025• 0 new comments

• improper declared type cause narrow type not work when its computed type is not union.

  #39114 commented onMay 12, 2025• 0 new comments

• Compile error if I named last array destructuring element.

  #41548 commented onMay 12, 2025• 0 new comments

• In JSDoc @type is not a type declaration, which it is much more like type conversion.

  #39650 commented onMay 12, 2025• 0 new comments

• Error when trying to assign a subclass of a base class with generics to `typeof` of that base class

  #41770 commented onMay 12, 2025• 0 new comments

• Correctly handle generic functions (e.g.: `Object.freeze`) passed as callbacks to generic functions (e.g.: `Array..map`)

  #42862 commented onMay 12, 2025• 0 new comments

• Broken emit when `Infinity` or `‑Infinity` ends up in a type position

  #42905 commented onMay 12, 2025• 0 new comments

• Typescript 4.2.x - incorrectly infered generic return type of a record union (extra undefined)

  #43943 commented onMay 12, 2025• 0 new comments

• Support inferring `never` as the return type in JavaScript when overriding a class method that returns `never`

  #46791 commented onMay 12, 2025• 0 new comments

• Intersection causes incorrect type compatability

  #48720 commented onMay 12, 2025• 0 new comments

• Regression in 4.8 where string union type widens to string

  #50635 commented onMay 12, 2025• 0 new comments

• Order of ReadonlySet/ReadonlyMap in union causes differing key inference

  #52313 commented onMay 12, 2025• 0 new comments

• Expression produces a union type that is too complex to represent

  #53234 commented onMay 12, 2025• 0 new comments

• Crash when defining `Array` type via `[]` syntax

  #57009 commented onMay 12, 2025• 0 new comments

• mapped type with remapped keys unexpectedly widens type

  #57265 commented onMay 12, 2025• 0 new comments

• Inconsistent type inference on overloaded function types

  #57351 commented onMay 12, 2025• 0 new comments

• Error not issued when global type is an alias of an object type literal

  #57564 commented onMay 12, 2025• 0 new comments

• Inconsistent typechecking with require() in JS and TS

  #60032 commented onMay 12, 2025• 0 new comments

• Need an option for ignore error when emit declaration

  #54305 commented onMay 12, 2025• 0 new comments

• Add types for RegExp.escape

  #61321 commented onMay 12, 2025• 0 new comments

• Add nested call and new expressions as potential intra expression inference sites

  #54183 commented onMay 12, 2025• 0 new comments

• ignore me, testing build stuff

  #55267 commented onMay 7, 2025• 0 new comments

• Support const assertions and unit type const variable references in constant expressions

  #59475 commented onMay 7, 2025• 0 new comments

• Stop reassigning `.valueDeclaration` to avoid replacing earlier declarations with late ones

  #60857 commented onMay 10, 2025• 0 new comments

• Cache mapper instantiations

  #61505 commented onMay 6, 2025• 0 new comments

• Fix #61429: Fast arithmetic type check for type-parameters upper-bounded by `bigint` fixed

  #61571 commented onMay 9, 2025• 0 new comments

• Bump /codeql-action from 3.28.15 to 3.28.16 in the -actions group

  #61625 commented onMay 12, 2025• 0 new comments

• docs(lib): add @throws JSDoc for BigInt methods and constructor

  #61653 commented onMay 6, 2025• 0 new comments

• Avoid resolving source prop type when the target is `unknown`/`any`

  #61660 commented onMay 7, 2025• 0 new comments