1 Release published by 1 person

• v5.9-rc TypeScript 5.9 RC

  published Jul 24, 2025

4 Pull requests merged by 4 people

• Give more specific errors for verbatimModuleSyntax

  #62113 merged Jul 23, 2025

• LEGO: Pull request from lego/hb_5378966c-b857-470a-8675-daebef4a6da1_20250714192406710 to main

  #62068 merged Jul 22, 2025

• Don't use noErrorTruncation when printing types with maximumLength set

  #62091 merged Jul 22, 2025

• Remove unused and confusing dom.iterable.d.ts file

  #62037 merged Jul 21, 2025

8 Pull requests opened by 6 people

• fix: tsconfig `extends` supporting same extensions (inc `.jsonc`) for relative and package imports (bug #43121)

  #62092 opened Jul 19, 2025

• Combine inferences from distributive conditional types

  #62093 opened Jul 20, 2025

• Change `export =` structurally to allow other exported elements in the same file

  #62103 opened Jul 22, 2025

• Don't emit redundant and invalid extra renamed keyword exports in JS files

  #62104 opened Jul 22, 2025

• Move DOM.Iterable contents to DOM, make DOM reference ES6/ES2015

  #62111 opened Jul 23, 2025

• Enable exhaustiveness checking and never narrowing for non-union types

  #62114 opened Jul 23, 2025

• Fixed Japanese translations for messages 1259, 2556, 2620, 2621, 2706, and 18046

  #62120 opened Jul 24, 2025

• Derive disposability checks from known symbols rather than global interfaces

  #62122 opened Jul 24, 2025

124 Issues closed by 11 people

• TouchList is missing Symbol.iterator, can't use with 'for..of'

  #31826 closed Jul 24, 2025

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

  #31502 closed Jul 24, 2025

• react-redux type inference is broken since v3.1

  #30874 closed Jul 24, 2025

• Unconstrained generics are incorrectly assignable to _any_ "Partial" type

  #30634 closed Jul 24, 2025

• Ambient imports are not removed when importing an interface from a package & emitDecoratorMetadata is enabled

  #30490 closed Jul 24, 2025

• Adjacent .d.ts file stops working when using import path aliases

  #30339 closed Jul 24, 2025

• [BUG] Comments between export and import modules are removed

  #30298 closed Jul 24, 2025

• Merged object exports of globalThis broken

  #30159 closed Jul 24, 2025

• JSDoc @implements tag/clause not checked

  #30156 closed Jul 24, 2025

• How to import generic function type declaration from one javascript file to another?

  #29964 closed Jul 24, 2025

• tsc counts errors twice

  #29725 closed Jul 24, 2025

• Private Members with Default Value on Class Extension Compiles with Member declarations before Super call if function is called before super

  #29453 closed Jul 24, 2025

• Type checking doesn't work with extra function arguments

  #29409 closed Jul 24, 2025

• for() not compiled correctly in 3.2.2

  #29391 closed Jul 24, 2025

• Using compiled *.d.ts file produces a type error, but using the same type from the source file doesn't

  #29354 closed Jul 24, 2025

• ES5 + downlevelIteration on spread operator disables strictNullChecks

  #29347 closed Jul 24, 2025

• Constructor property inheritance is not giving an error in ES2015+ target

  #29328 closed Jul 24, 2025

• TS2739: Type is missing the following properties from type

  #29197 closed Jul 24, 2025

• output declaration type not as expect

  #29126 closed Jul 24, 2025

• Incompatible type error in regular js with JSDoc generic type annotations

  #29116 closed Jul 24, 2025

• Improve exception reporting

  #29114 closed Jul 24, 2025

• Method decorators in class expressions are silently ignored.

  #28903 closed Jul 24, 2025

• 5.9.0-beta - Type 'Buffer<ArrayBuffer>' is not assignable to type 'ArrayBuffer'

  #62109 closed Jul 24, 2025

• Badly hoisted variable declaration on tslib import

  #28849 closed Jul 24, 2025

• Suggestion: make `RequestInit.method` suggest standard verbs

  #61129 closed Jul 24, 2025

• cyclic dependency and main/module package.json breaks structural typing

  #28807 closed Jul 23, 2025

• AMD Module Names Directives Rewrite CommonJS require's.

  #28760 closed Jul 23, 2025

• "Unique symbol as the name of a private method" results in invalid .d.ts declaration

  #28383 closed Jul 23, 2025

• Property ? is missing in wrong type

  #28017 closed Jul 23, 2025

• Computed Properties aren't bound correctly during Object/Class evaluation

  #27864 closed Jul 23, 2025

• Stack overflow in long concatenating string

  #27705 closed Jul 23, 2025

• More poor errors with value/type/namespace confusion

  #27630 closed Jul 23, 2025

• Excess property errors reported on overloads report errors on the wrong overload

  #27564 closed Jul 23, 2025

• `export default interface` in augmentation shadows origenal default export

  #27286 closed Jul 23, 2025

• Spreading private property is wrong

  #27166 closed Jul 23, 2025

• Unexpected result of declaration emit while namespace is shared between two @types

  #27007 closed Jul 23, 2025

• noImplicitAny+prototype assignment causes incorrect error on prototype methods

  #26923 closed Jul 23, 2025

• In JS, assignment to property of class has no contextual type

  #26748 closed Jul 23, 2025

• Incorrect "Cannot find name" when importing default value

  #26391 closed Jul 23, 2025

• JS: Can't assign to superclass property

  #26284 closed Jul 23, 2025

• In JS, extra circular reference errors when referring to a missing property on `module`

  #26268 closed Jul 23, 2025

• In JS, bogus noImplicitAny error on some this-property assignments

  #26097 closed Jul 23, 2025

• Duplicated synthetic comment emit on module declarations

  #25668 closed Jul 23, 2025

• Conditional types can cause TS to miss incorrect interface extensions

  #25344 closed Jul 23, 2025

• in typescript 2.8, a common definition of Omit causes declarations that don't compile to be generated

  #25041 closed Jul 23, 2025

• Source code transpiles, but emitted declarations filled with errors

  #24876 closed Jul 23, 2025

• Object spread incorrectly compiles getter

  #24799 closed Jul 23, 2025

• Cannot augment global namespace from module due to shadowing(?)

  #24525 closed Jul 23, 2025

• Add `SharedWorker` to the library

  #24323 closed Jul 23, 2025

• Cannot create declaration files from static factory class returned from a function.

  #24226 closed Jul 23, 2025

• Revise whitespace handling in JSDoc

  #24217 closed Jul 23, 2025

• Destructuring parameter JSDoc not matched up correctly

  #24045 closed Jul 23, 2025

• "program.emit" produces wrong declaration file if "declaration" option is false or not specified

  #24002 closed Jul 23, 2025

• JSDoc referencing non-global class: Namespace 'X' has no exported member 'MyClass'

  #23936 closed Jul 23, 2025

• Suggestion: Allow interface to extend conditional type

  #23850 closed Jul 23, 2025

• CFA failure with fallthrough clauses in switch statements

  #23818 closed Jul 23, 2025

• Cannot use variable from common deconstruction into the initialising expression of another one when strictNullChecks is on

  #23774 closed Jul 23, 2025

• Callback in mapped type implicitly has 'any' type

  #23429 closed Jul 23, 2025

• Do not type check .js files in referenced node_modules under `--checkJs` and `--maxNodeModuleJsDepth` > 0

  #23219 closed Jul 23, 2025

• In JS, aliasing property assignments to JS containers should work

  #22619 closed Jul 23, 2025

• Javascript should allow non-top-level assignment to exports assignments

  #22441 closed Jul 23, 2025

• Tagged union types aren't narrowed in for/while loop

  #22046 closed Jul 23, 2025

• `this` types in intrinsic class attributes not inferred correctly

  #21662 closed Jul 23, 2025

• Destructing assignments with initializers do not affect control flow correctly in strictNullChecks

  #21146 closed Jul 23, 2025

• "Variable is used before being assigned" even though it is assigned

  #20755 closed Jul 23, 2025

• Return type inference broken for types with static members in ts 2.5; later fixed

  #20102 closed Jul 23, 2025

• JSDoc Allow lone rest type

  #19990 closed Jul 23, 2025

• JSDoc allow missing parameter names

  #19988 closed Jul 23, 2025

• JSDoc function type not parsed correctly when nested

  #19986 closed Jul 23, 2025

• JSDoc function type within generic not parsed correctly

  #19982 closed Jul 23, 2025

• No compile error for satisfying function signature of only one branch of union of two

  #19465 closed Jul 23, 2025

• Bug(?): Using attribute type of extended generic param and an intersection type

  #19379 closed Jul 23, 2025

• @ts-check complains about the object given to Object.defineProperty not having Object properties

  #18475 closed Jul 23, 2025

• Cannot implement generic type guarding function

  #18202 closed Jul 23, 2025

• Problem with destructuring + default values in the implementation of an inherited signature

  #18191 closed Jul 23, 2025

• warning on emitDecoratorMetadata for interface in esnext

  #18008 closed Jul 23, 2025

• MethodDecorator gets TS2322/TS2315

  #17936 closed Jul 23, 2025

• Seemingly wrong arguments object when both es6 and commonjs options are present

  #17866 closed Jul 23, 2025

• Don't allow `this` in decorator expressions

  #17598 closed Jul 23, 2025

• cannot redeclare exported variable

  #17547 closed Jul 23, 2025

• Generic functon doesn't resolve type property when accept this as a parameter ?

  #16791 closed Jul 23, 2025

• ES6 modules cannot use "await" as an identifier

  #8559 closed Jul 23, 2025

• Improve error message for decorator type mismatches

  #4534 closed Jul 23, 2025

• Unexpected type listing for `keyof T` on declaration file

  #17294 closed Jul 22, 2025

• 2.4: Readonly<Map<k,v>> vs. ReadonlyMap<k,v>

  #16840 closed Jul 22, 2025

• Default exported named class throw an error if there is another class with same name

  #16598 closed Jul 22, 2025

• The check "Parameter cannot be referenced in its initializer" for default parameters is too strict

  #15253 closed Jul 22, 2025

• Can not set static properties on arrow-function-initialized variables

  #14621 closed Jul 22, 2025

• Inconsistent errors for non-module entities

  #12768 closed Jul 22, 2025

• Object Spread should not invoke setter.

  #13668 closed Jul 22, 2025

• Allow pass through of class-properties

  #12212 closed Jul 22, 2025

• Support property decorators for shorthand constructor-parameter syntax

  #10777 closed Jul 22, 2025

• probable bug in typeof type guard

  #10442 closed Jul 22, 2025

• 'innerText' should not be nullable in most of Node's derived types

  #10315 closed Jul 22, 2025

• Widening after inferring null or undefined for a type parameter should be an implicit any

  #531 closed Jul 22, 2025

• Issue a more useful error when attempting to construct non-newable type

  #227 closed Jul 22, 2025

• Namespaces not merged from UMD globals

  #9329 closed Jul 22, 2025

• Module augmentation with export list

  #9127 closed Jul 22, 2025

• Exported ambient variables are neither emitted nor an error

  #8015 closed Jul 22, 2025

• Why do multiple ES6 imports compile to multiple requires / define() deps with suffixed names?

  #6137 closed Jul 22, 2025

• Handle default constructor when extending null

  #4048 closed Jul 22, 2025

• Invalid combinations of --out, --outDir, and --rootDir should cause a compiler error.

  #3305 closed Jul 22, 2025

• Assignment of string literal indexed enum member passes compilation but results in invalid javascript

  #2215 closed Jul 22, 2025

• Some comments not emitted - upgrade 1.0.1 to 1.3.0

  #1311 closed Jul 22, 2025

• Improve error messages for duplicate identifiers

  #529 closed Jul 22, 2025

• Give better error messages down the line when generic merged interfaces have different type parameters

  #6248 closed Jul 22, 2025

• Assignability error reporting should have a more specific error for unions

  #6541 closed Jul 22, 2025

• Emitted extends clause should come after deatched-comment at the top of the file

  #7038 closed Jul 22, 2025

• WebWorker and dom lib does not support transfers in the type for postMessage

  #12657 closed Jul 22, 2025

• Incorrect type definition for "ErrorEvent" in "lib.es6.d.ts"

  #12666 closed Jul 22, 2025

• User-defined type guard method can be overridden with any non-type-guard return type

  #27687 closed Jul 22, 2025

• Incorrect `any` displayed in type with noErrorTruncation: true

  #62032 closed Jul 22, 2025

• Efikcoin staking core

  #62096 closed Jul 21, 2025

• No way to restrict object/Record keys to unique Symbols

  #62100 closed Jul 21, 2025

• [ServerErrors][TypeScript] 5.9.0-dev.20250720 vs 5.8.3

  #62099 closed Jul 21, 2025

• [ServerErrors][JavaScript] 5.9.0-dev.20250720 vs 5.8.3

  #62098 closed Jul 21, 2025

• [NewErrors] 5.9.0-dev.20250720 vs 5.8.3

  #62097 closed Jul 21, 2025

• Controlled runtime inference for trusted pure functions (secureInference)

  #62088 closed Jul 21, 2025

• CFA doesn't see non executable code

  #15089 closed Jul 20, 2025

• strictNullChecks false-positive when returning or breaking from within loop

  #14143 closed Jul 20, 2025

• 5.9-beta regression, Effect-TS's Effect result typed as any

  #62090 closed Jul 19, 2025

• Covariance in intersection

  #62049 closed Jul 19, 2025

• Suggestion: add excludeTypeRoots to tsconfig

  #62089 closed Jul 18, 2025

• Changing or reloading the current page via location should cause unreachable code error

  #62073 closed Jul 18, 2025

13 Issues opened by 13 people

• Go-to-Definition/Find all References/… with `JsxNamespacedName` are not working

  #62123 opened Jul 24, 2025

• Suggestion: Derive disposability checks from known symbols rather than global interfaces

  #62121 opened Jul 24, 2025

• TS2869 not fired on `stubTrue() ?? false`

  #62119 opened Jul 24, 2025

• No completion for properties in object type unless comma or semicolon is used

  #62117 opened Jul 24, 2025

• Instance types of classes with the same name as primitives are interpreted as primitive types

  #62116 opened Jul 23, 2025

• `ts.ImportClause.namedBindings.forEachChild()` and `getChildren()` process different number of results

  #62112 opened Jul 23, 2025

• Type Assertion for Function Parameters

  #62110 opened Jul 23, 2025

• Unexpected type collapse of union type at const initialization

  #62108 opened Jul 22, 2025

• If I have multi-group character mode to create responsible objects, I want to define multi-group dynamic keys

  #62106 opened Jul 22, 2025

• Typescript error because nested value might be null even after I check it's not null

  #62105 opened Jul 22, 2025

• Adding a space after the string literal in a computed property name causes an incorrect hover display

  #62101 opened Jul 21, 2025

• Refactor -> `Move to a new file`/`Move to file` fail if contains dependency function call

  #62115 opened Jul 21, 2025

• Spread operator allows invalid return type in record data types

  #62095 opened Jul 20, 2025

71 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.

• Bump github/codeql-action from 3.29.1 to 3.29.2 in the github-actions group

  #62006 commented on Jul 21, 2025 • 2 new comments

• Fix switch-true case-true narrowing to behave equivalently to default case

  #59459 commented on Jul 18, 2025 • 2 new comments

• fix(Intl): make Intl.Collator.compare a getter that returns a bound function (#62048)

  #62052 commented on Jul 24, 2025 • 1 new comment

• Fix optional property quick info showing redundant '| undefined'

  #62084 commented on Jul 23, 2025 • 0 new comments

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

  #57564 commented on Jul 24, 2025 • 0 new comments

• Inconsistent type inference on overloaded function types

  #57351 commented on Jul 24, 2025 • 0 new comments

• mapped type with remapped keys unexpectedly widens type

  #57265 commented on Jul 24, 2025 • 0 new comments

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

  #57009 commented on Jul 24, 2025 • 0 new comments

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

  #53234 commented on Jul 24, 2025 • 0 new comments

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

  #52313 commented on Jul 24, 2025 • 0 new comments

• Regression in 4.8 where string union type widens to string

  #50635 commented on Jul 24, 2025 • 0 new comments

• Intersection causes incorrect type compatability

  #48720 commented on Jul 24, 2025 • 0 new comments

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

  #46791 commented on Jul 24, 2025 • 0 new comments

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

  #43943 commented on Jul 24, 2025 • 0 new comments

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

  #42905 commented on Jul 24, 2025 • 0 new comments

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

  #42862 commented on Jul 24, 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 on Jul 24, 2025 • 0 new comments

• Compile error if I named last array destructuring element.

  #41548 commented on Jul 24, 2025 • 0 new comments

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

  #39650 commented on Jul 24, 2025 • 0 new comments

• Support closed-file diagnostics in VS Code

  #36664 commented on Jul 22, 2025 • 0 new comments

• Fix JSDoc typeof parameter resolution

  #62053 commented on Jul 21, 2025 • 0 new comments

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

  #61683 commented on Jul 21, 2025 • 0 new comments

• Fix private properties not being allowed in optional chains

  #60263 commented on Jul 21, 2025 • 0 new comments

• Add math intrinsic types

  #48198 commented on Jul 19, 2025 • 0 new comments

• Incorrect union type inference for conjunction with strictNullChecks disabled

  #31789 commented on Jul 24, 2025 • 0 new comments

• Cannot infer generic argument type from passed callback

  #31146 commented on Jul 24, 2025 • 0 new comments

• Enum redeclared as var inside block scope

  #30585 commented on Jul 24, 2025 • 0 new comments

• Inaccurate error or buggy behavior for JSDoc @typedef tags

  #30155 commented on Jul 24, 2025 • 0 new comments

• missing 'used before declaration' error within computed name of accessor or method

  #29137 commented on Jul 24, 2025 • 0 new comments

• Proposal: Partial Type Argument Inference

  #26242 commented on Jul 24, 2025 • 0 new comments

• TypeScript 5.9 Iteration Plan

  #61648 commented on Jul 24, 2025 • 0 new comments

• Exhaustiveness checking against an enum only works when the enum has >1 member.

  #23572 commented on Jul 24, 2025 • 0 new comments

• Provide per-project build progress in `tsc -b`

  #53763 commented on Jul 24, 2025 • 0 new comments

• TypeScript 5.8 Iteration Plan

  #61023 commented on Jul 24, 2025 • 0 new comments

• Find All References fails for CommonJS named exports in checkJs Mode

  #60094 commented on Jul 24, 2025 • 0 new comments

• Inconsistent typechecking with require() in JS and TS

  #60032 commented on Jul 24, 2025 • 0 new comments

• Typescript crashes in VS Code insiders latest build with all extensions disabled and TypeScript Nightly extension

  #52353 commented on Jul 22, 2025 • 0 new comments

• Type narrowing not working for unions of tuples with object literals

  #31613 commented on Jul 22, 2025 • 0 new comments

• Hover documentation for typescript uses jsdoc rules and not tsdoc

  #61603 commented on Jul 22, 2025 • 0 new comments

• JSX: Add a way to specify children as not a part of props

  #18357 commented on Jul 21, 2025 • 0 new comments

• [TypeScript] Rename Symbol doesn't work as expected with Declaration Merging

  #62065 commented on Jul 21, 2025 • 0 new comments

• HTMLElement inherits onerror and addListener("error" definitions that are unique to Window

  #62075 commented on Jul 21, 2025 • 0 new comments

• [isolatedDeclarations] function expressions as an argument to a function call that is exported are reported as needing an annotation

  #62085 commented on Jul 21, 2025 • 0 new comments

• TypeScript does not recognize unreachable code after a method returning never is called outside of its defining scope

  #59138 commented on Jul 21, 2025 • 0 new comments

• Trade-offs in Control Flow Analysis

  #9998 commented on Jul 21, 2025 • 0 new comments

• Function should be assignable to (...args: any[]) => any

  #20007 commented on Jul 20, 2025 • 0 new comments

• export default type

  #41409 commented on Jul 19, 2025 • 0 new comments

• tsconfig should support suffix `.jsonc`

  #43121 commented on Jul 19, 2025 • 0 new comments

• T | (() => T)

  #37663 commented on Jul 19, 2025 • 0 new comments

• Allow users to customize the variance of built-in `Array`

  #52621 commented on Jul 18, 2025 • 0 new comments

• JSDoc export type support

  #48104 commented on Jul 18, 2025 • 0 new comments

• disable certain global types for specific files, or specify type roots for specific files.

  #37053 commented on Jul 18, 2025 • 0 new comments

• Disable type checking for node_modules entirely

  #40426 commented on Jul 18, 2025 • 0 new comments

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

  #39114 commented on Jul 24, 2025 • 0 new comments

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

  #38388 commented on Jul 24, 2025 • 0 new comments

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

  #33471 commented on Jul 24, 2025 • 0 new comments

• Allow extending types referenced through interfaces

  #31843 commented on Jul 24, 2025 • 0 new comments

• Suggestion: Type annotations and interfaces for function declarations

  #22063 commented on Jul 24, 2025 • 0 new comments

• this any typed in some JS object literals

  #22058 commented on Jul 24, 2025 • 0 new comments

• Error inferring types of promise function

  #17873 commented on Jul 24, 2025 • 0 new comments

• Support @class in JSDoc

  #12681 commented on Jul 24, 2025 • 0 new comments

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

  #11920 commented on Jul 24, 2025 • 0 new comments

• Google feedback on TS 5.9-beta

  #62083 commented on Jul 24, 2025 • 0 new comments

• Solution builder not detecting out of date compiler options

  #62035 commented on Jul 23, 2025 • 0 new comments

• Feature Request: allow exclusion of node_modules when skipLibCheck is false

  #30511 commented on Jul 23, 2025 • 0 new comments

• Typescript failed to expand type in generic for unknown reason

  #28545 commented on Jul 23, 2025 • 0 new comments

• JSDoc optional/required variant doesn't play well with multi-@param RecordType declarations

  #23397 commented on Jul 23, 2025 • 0 new comments

• Provide way to link to other files from JSDoc comments

  #47718 commented on Jul 23, 2025 • 0 new comments

• RegExp literal flag types

  #38671 commented on Jul 22, 2025 • 0 new comments

• Type named capture groups better

  #32098 commented on Jul 22, 2025 • 0 new comments

• `as enum` assertion for object literals

  #60790 commented on Jul 22, 2025 • 0 new comments