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manthansubhash01 · 2026-03-24T17:26:56Z

Summary

This PR adds support for jest.config.mts as a valid Jest configuration file.

Jest currently supports jest.config.ts, jest.config.js, jest.config.mjs, jest.config.cjs, jest.config.cts, and jest.config.json, but does not support the TypeScript ESM extension .mts. This creates friction in ESM-first TypeScript projects where .mts is used to explicitly define ESM behavior independent of the package.json type field.

This change resolves the issue by:

Adding .mts to config extension constants and implicit config resolution order.
Updating config loading to treat .mts as TypeScript and load it via ESM.
Updating the module loading helper to use dynamic import for .mts.
Adding and updating unit tests and e2e tests for config discovery and loading.
Adding fixtures for .mts config scenarios.
Updating CLI extension validation test expectations.
Updating documentation (current and versioned) to include .mts as a supported config file.

Test plan

Attempted to run targeted tests for all modified areas.

Result:

Test execution could not be completed in this environment due to missing dependencies.
Error observed: Couldn't find the node_modules state file - running an install might help.

Additional validation:

No editor or type errors were reported for the modified files.

CI:

Full test validation is expected to run in CI for this branch.

Note:

A CHANGELOG.md entry will be added before merge, as per contribution guidelines.

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linux-foundation-easycla · 2026-03-24T17:27:05Z

The committers listed above are authorized under a signed CLA.

✅ login: manthansubhash01 / name: manthansubhash01 (3c8cd16, 5c39617, 919e4de, c7e584f)
✅ login: SimenB / name: Simen Bekkhus (5015a4f, 533c0f1, 7af8bd9, a4c7e04, ce4cd54, e08317c, f6f6d3d, fd03360)

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commit: 7af8bd9

SimenB

Thanks!

SimenB · 2026-05-07T19:05:47Z

https://github.com/jestjs/jest/releases/tag/v30.4.0

| datasource | package | from | to | | ---------- | ------- | ------ | ------ | | npm | jest | 30.3.0 | 30.4.0 | ## [v30.4.0](https://github.com/jestjs/jest/blob/HEAD/CHANGELOG.md#3040) ##### Features - `[babel-jest]` Support collecting coverage from `.mts`, `.cts` (and other) files ([#15994](jestjs/jest#15994)) - `[jest-circus, jest-cli, jest-config, jest-core, jest-jasmine2, jest-types]` Add `--collect-tests` flag to discover and list tests without executing them ([#16006](jestjs/jest#16006)) - `[jest-config, jest-runner, jest-worker]` Add `workerGracefulExitTimeout` config option to control how long workers are given to exit before being force-killed ([#15984](jestjs/jest#15984)) - `[jest-config]` Add support for `jest.config.mts` as a valid configuration file ([#16005](jestjs/jest#16005)) - `[jest-config, jest-core, jest-reporters, jest-runner]` `verbose` and `silent` can now be set per-project; the project-level value overrides the global value for that project's tests ([#16133](jestjs/jest#16133)) - `[@jest/fake-timers]` Accept `Temporal.Duration` in `jest.advanceTimersByTime()` and `jest.advanceTimersByTimeAsync()` ([#16128](jestjs/jest#16128)) - `[@jest/fake-timers]` Accept `Temporal.Instant` and `Temporal.ZonedDateTime` in `jest.setSystemTime()` and `useFakeTimers({now})` ([#16128](jestjs/jest#16128)) - `[@jest/fake-timers]` Support faking `Temporal.Now.*` ([#16131](jestjs/jest#16131)) - `[jest-mock]` Add `clearMocksOnScope(scope)` on `ModuleMocker` for clearing every mock function exposed on a scope object ([#16088](jestjs/jest#16088)) - `[jest-resolve]` Add `canResolveSync()` on `Resolver` so callers can detect when a user-configured resolver only exports an `async` hook ([#16064](jestjs/jest#16064)) - `[jest-runtime]` Use synchronous `evaluate()` for ES modules without top-level `await` on Node versions that support it (v24.9+), and prefer the synchronous transform path when a sync transformer is configured ([#16062](jestjs/jest#16062)) - `[jest-runtime]` Support `require()` of ES modules on Node v24.9+ ([#16074](jestjs/jest#16074)) - `[jest-runtime]` Validate TC39 import attributes (`with { type: 'json' }`) on ESM imports ([#16127](jestjs/jest#16127)) - `[@jest/transform]` Add `canTransformSync(filename)` on `ScriptTransformer` so callers can pick the sync vs async transform path ([#16062](jestjs/jest#16062)) - `[jest-util]` Add `isError` helper ([#16076](jestjs/jest#16076)) - `[pretty-format]` Support React 19 ([#16123](jestjs/jest#16123)) ##### Fixes - `[expect-utils]` Fix `toStrictEqual` failing on `structuredClone` results due to cross-realm constructor mismatch ([#15959](jestjs/jest#15959)) - `[@jest/expect-utils]` Prevent `toMatchObject`/subset matching from throwing when encountering exotic iterables ([#15952](jestjs/jest#15952)) - `[fake-timers]` Convert `Date` to milliseconds before passing to `@sinonjs/fake-timers` ([#16029](jestjs/jest#16029)) - `[jest]` Export `GlobalConfig` and `ProjectConfig` TypeScript types ([#16132](jestjs/jest#16132)) - `[jest-circus]` Prevent crash when `asyncError` is undefined for non-Error throws ([#16003](jestjs/jest#16003)) - `[jest-circus, jest-jasmine2]` Include `Error.cause` in JSON `failureMessages` output ([#15967](jestjs/jest#15967)) - `[jest-config]` Fix preset path resolution on Windows when the preset uses subpath `exports` ([#15961](jestjs/jest#15961)) - `[jest-config]` Allow `collectCoverage` and `coverageProvider` in project config without a validation warning ([#16132](jestjs/jest#16132)) - `[jest-config]` Project config validator now emits "is not supported in an individual project configuration" instead of "probably a typing mistake" for known global-only options ([#16132](jestjs/jest#16132)) - `[jest-environment-node]` Fix `--localstorage-file` warning on Node 25+ ([#16086](jestjs/jest#16086)) - `[jest-reporters]` Apply global coverage threshold to unmatched pattern files in addition to glob/path thresholds ([#16137](jestjs/jest#16137)) - `[jest-reporters, jest-runner, jest-runtime, jest-transform]` Fix coverage report not showing correct code coverage when using `projects` config option ([#16140](jestjs/jest#16140)) - `[jest-runtime]` Resolve `expect` and `@jest/expect` from the internal module registry so test-file imports share the same `JestAssertionError` as the global `expect` ([#16130](jestjs/jest#16130)) - `[jest-runtime]` Improve CJS-from-ESM interop: `__esModule`/Babel default unwrap, broader named-export coverage, and shared CJS singleton across importers ([#16050](jestjs/jest#16050)) - `[jest-runtime]` Load `.js` files with ESM syntax but no `"type":"module"` marker as native ESM ([#16050](jestjs/jest#16050)) - `[jest-runtime]` Extend the `.js`-with-ESM-syntax fallback to `require()` on Node v24.9+ - falls back to `require(esm)` when the CJS parser rejects ESM syntax ([#16078](jestjs/jest#16078)) - `[jest-runtime]` Fix deadlocks and double-evaluation in concurrent ESM and wasm imports ([#16050](jestjs/jest#16050)) - `[jest-runtime]` Fix error when `require()` is called after the Jest environment has been torn down ([#15951](jestjs/jest#15951)) - `[jest-runtime]` Fix missing error when `import()` is called after the Jest environment has been torn down ([#16080](jestjs/jest#16080)) - `[jest-runtime]` Fix virtual `unstable_mockModule` registrations not respected in ESM ([#16081](jestjs/jest#16081)) - `[jest-runtime]` Apply `moduleNameMapper` when resolving modules with `require.resolve()` and the `paths` option ([#16135](jestjs/jest#16135)) ##### Chore & Maintenance - `[@jest/fake-timers]` Upgrade `@sinonjs/fake-timers` ([#16139](jestjs/jest#16139)) - `[jest-runtime]` Use synchronous `linkRequests` / `instantiate` for ESM linking on Node v24.9+ ([#16063](jestjs/jest#16063))

| datasource | package | from | to | | ---------- | ------- | ------ | ------ | | npm | jest | 30.3.0 | 30.4.2 | ## [v30.4.2](https://github.com/jestjs/jest/blob/HEAD/CHANGELOG.md#3042) ##### Fixes - `[jest-runtime]` Fix named imports from CJS modules whose `module.exports` is a function with own-property exports ([#16150](jestjs/jest#16150)) ## [v30.4.1](https://github.com/jestjs/jest/blob/HEAD/CHANGELOG.md#3041) ##### Features - `[jest-config, jest-core, jest-runner, jest-schemas, jest-types]` Allow custom runner configuration options via tuple format `['runner-path', {options}]` ([#16141](jestjs/jest#16141)) ##### Fixes - `[jest-runtime]` Align CJS-from-ESM default export with Node: `module.exports` is always the ESM default, `__esModule` unwrapping is no longer applied ([#16143](jestjs/jest#16143)) ## [v30.4.0](https://github.com/jestjs/jest/blob/HEAD/CHANGELOG.md#3040) ##### Features - `[babel-jest]` Support collecting coverage from `.mts`, `.cts` (and other) files ([#15994](jestjs/jest#15994)) - `[jest-circus, jest-cli, jest-config, jest-core, jest-jasmine2, jest-types]` Add `--collect-tests` flag to discover and list tests without executing them ([#16006](jestjs/jest#16006)) - `[jest-config, jest-runner, jest-worker]` Add `workerGracefulExitTimeout` config option to control how long workers are given to exit before being force-killed ([#15984](jestjs/jest#15984)) - `[jest-config]` Add support for `jest.config.mts` as a valid configuration file ([#16005](jestjs/jest#16005)) - `[jest-config, jest-core, jest-reporters, jest-runner]` `verbose` and `silent` can now be set per-project; the project-level value overrides the global value for that project's tests ([#16133](jestjs/jest#16133)) - `[@jest/fake-timers]` Accept `Temporal.Duration` in `jest.advanceTimersByTime()` and `jest.advanceTimersByTimeAsync()` ([#16128](jestjs/jest#16128)) - `[@jest/fake-timers]` Accept `Temporal.Instant` and `Temporal.ZonedDateTime` in `jest.setSystemTime()` and `useFakeTimers({now})` ([#16128](jestjs/jest#16128)) - `[@jest/fake-timers]` Support faking `Temporal.Now.*` ([#16131](jestjs/jest#16131)) - `[jest-mock]` Add `clearMocksOnScope(scope)` on `ModuleMocker` for clearing every mock function exposed on a scope object ([#16088](jestjs/jest#16088)) - `[jest-resolve]` Add `canResolveSync()` on `Resolver` so callers can detect when a user-configured resolver only exports an `async` hook ([#16064](jestjs/jest#16064)) - `[jest-runtime]` Use synchronous `evaluate()` for ES modules without top-level `await` on Node versions that support it (v24.9+), and prefer the synchronous transform path when a sync transformer is configured ([#16062](jestjs/jest#16062)) - `[jest-runtime]` Support `require()` of ES modules on Node v24.9+ ([#16074](jestjs/jest#16074)) - `[jest-runtime]` Validate TC39 import attributes (`with { type: 'json' }`) on ESM imports ([#16127](jestjs/jest#16127)) - `[@jest/transform]` Add `canTransformSync(filename)` on `ScriptTransformer` so callers can pick the sync vs async transform path ([#16062](jestjs/jest#16062)) - `[jest-util]` Add `isError` helper ([#16076](jestjs/jest#16076)) - `[pretty-format]` Support React 19 ([#16123](jestjs/jest#16123)) ##### Fixes - `[expect-utils]` Fix `toStrictEqual` failing on `structuredClone` results due to cross-realm constructor mismatch ([#15959](jestjs/jest#15959)) - `[@jest/expect-utils]` Prevent `toMatchObject`/subset matching from throwing when encountering exotic iterables ([#15952](jestjs/jest#15952)) - `[fake-timers]` Convert `Date` to milliseconds before passing to `@sinonjs/fake-timers` ([#16029](jestjs/jest#16029)) - `[jest]` Export `GlobalConfig` and `ProjectConfig` TypeScript types ([#16132](jestjs/jest#16132)) - `[jest-circus]` Prevent crash when `asyncError` is undefined for non-Error throws ([#16003](jestjs/jest#16003)) - `[jest-circus, jest-jasmine2]` Include `Error.cause` in JSON `failureMessages` output ([#15967](jestjs/jest#15967)) - `[jest-config]` Fix preset path resolution on Windows when the preset uses subpath `exports` ([#15961](jestjs/jest#15961)) - `[jest-config]` Allow `collectCoverage` and `coverageProvider` in project config without a validation warning ([#16132](jestjs/jest#16132)) - `[jest-config]` Project config validator now emits "is not supported in an individual project configuration" instead of "probably a typing mistake" for known global-only options ([#16132](jestjs/jest#16132)) - `[jest-environment-node]` Fix `--localstorage-file` warning on Node 25+ ([#16086](jestjs/jest#16086)) - `[jest-reporters]` Apply global coverage threshold to unmatched pattern files in addition to glob/path thresholds ([#16137](jestjs/jest#16137)) - `[jest-reporters, jest-runner, jest-runtime, jest-transform]` Fix coverage report not showing correct code coverage when using `projects` config option ([#16140](jestjs/jest#16140)) - `[jest-runtime]` Resolve `expect` and `@jest/expect` from the internal module registry so test-file imports share the same `JestAssertionError` as the global `expect` ([#16130](jestjs/jest#16130)) - `[jest-runtime]` Improve CJS-from-ESM interop: `__esModule`/Babel default unwrap, broader named-export coverage, and shared CJS singleton across importers ([#16050](jestjs/jest#16050)) - `[jest-runtime]` Load `.js` files with ESM syntax but no `"type":"module"` marker as native ESM ([#16050](jestjs/jest#16050)) - `[jest-runtime]` Extend the `.js`-with-ESM-syntax fallback to `require()` on Node v24.9+ - falls back to `require(esm)` when the CJS parser rejects ESM syntax ([#16078](jestjs/jest#16078)) - `[jest-runtime]` Fix deadlocks and double-evaluation in concurrent ESM and wasm imports ([#16050](jestjs/jest#16050)) - `[jest-runtime]` Fix error when `require()` is called after the Jest environment has been torn down ([#15951](jestjs/jest#15951)) - `[jest-runtime]` Fix missing error when `import()` is called after the Jest environment has been torn down ([#16080](jestjs/jest#16080)) - `[jest-runtime]` Fix virtual `unstable_mockModule` registrations not respected in ESM ([#16081](jestjs/jest#16081)) - `[jest-runtime]` Apply `moduleNameMapper` when resolving modules with `require.resolve()` and the `paths` option ([#16135](jestjs/jest#16135)) ##### Chore & Maintenance - `[@jest/fake-timers]` Upgrade `@sinonjs/fake-timers` ([#16139](jestjs/jest#16139)) - `[jest-runtime]` Use synchronous `linkRequests` / `instantiate` for ESM linking on Node v24.9+ ([#16063](jestjs/jest#16063))

Support jest.config.mts

919e4de

manthansubhash01 and others added 4 commits March 24, 2026 23:44

Fix .mts e2e on Node 18/20

5c39617

Fix lint

3c8cd16

Fix lint formatting

c7e584f

Merge branch 'main' into feat/support-jest-config-mts-15997

5015a4f

SimenB reviewed May 3, 2026

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Comment thread website/versioned_docs/version-30.0/Configuration.md Outdated

SimenB added 7 commits May 3, 2026 16:14

Apply suggestion from @SimenB

7af8bd9

Merge branch 'main' into feat/support-jest-config-mts-15997

e08317c

changelog

a4c7e04

reorder extenions

f6f6d3d

no need to try require of mts

ce4cd54

reorder in docs as well

fd03360

meh

533c0f1

SimenB approved these changes May 4, 2026

View reviewed changes

SimenB merged commit 42de652 into jestjs:main May 4, 2026
89 of 90 checks passed

This was referenced May 5, 2026

feat(jest-config): supports Jest config file with .mts extension #15796

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[Feature]: Support jest.config.mts config file extension #15997

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