Support jest.config.mts

[manthansubhash01]

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.

[netlify]

✅ Deploy Preview for jestjs ready!

Built without sensitive environment variables

Name	Link
🔨 Latest commit	c7e584f
🔍 Latest deploy log	https://app.netlify.com/projects/jestjs/deploys/69c2ddf85e328d0008899273
😎 Deploy Preview	https://deploy-preview-16005--jestjs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: manthansubhash01 / name: Manthan Ziman (3c8cd16, 5c39617, 919e4de, c7e584f)

[pkg-pr-new]

Open in StackBlitz

babel-jest

npm i https://pkg.pr.new/babel-jest@16005

babel-plugin-jest-hoist

npm i https://pkg.pr.new/babel-plugin-jest-hoist@16005

babel-preset-jest

npm i https://pkg.pr.new/babel-preset-jest@16005

create-jest

npm i https://pkg.pr.new/create-jest@16005

@jest/diff-sequences

npm i https://pkg.pr.new/@jest/diff-sequences@16005

expect

npm i https://pkg.pr.new/expect@16005

@jest/expect-utils

npm i https://pkg.pr.new/@jest/expect-utils@16005

jest

npm i https://pkg.pr.new/jest@16005

jest-changed-files

npm i https://pkg.pr.new/jest-changed-files@16005

jest-circus

npm i https://pkg.pr.new/jest-circus@16005

jest-cli

npm i https://pkg.pr.new/jest-cli@16005

jest-config

npm i https://pkg.pr.new/jest-config@16005

@jest/console

npm i https://pkg.pr.new/@jest/console@16005

@jest/core

npm i https://pkg.pr.new/@jest/core@16005

@jest/create-cache-key-function

npm i https://pkg.pr.new/@jest/create-cache-key-function@16005

jest-diff

npm i https://pkg.pr.new/jest-diff@16005

jest-docblock

npm i https://pkg.pr.new/jest-docblock@16005

jest-each

npm i https://pkg.pr.new/jest-each@16005

@jest/environment

npm i https://pkg.pr.new/@jest/environment@16005

jest-environment-jsdom

npm i https://pkg.pr.new/jest-environment-jsdom@16005

@jest/environment-jsdom-abstract

npm i https://pkg.pr.new/@jest/environment-jsdom-abstract@16005

jest-environment-node

npm i https://pkg.pr.new/jest-environment-node@16005

@jest/expect

npm i https://pkg.pr.new/@jest/expect@16005

@jest/fake-timers

npm i https://pkg.pr.new/@jest/fake-timers@16005

@jest/get-type

npm i https://pkg.pr.new/@jest/get-type@16005

@jest/globals

npm i https://pkg.pr.new/@jest/globals@16005

jest-haste-map

npm i https://pkg.pr.new/jest-haste-map@16005

jest-jasmine2

npm i https://pkg.pr.new/jest-jasmine2@16005

jest-leak-detector

npm i https://pkg.pr.new/jest-leak-detector@16005

jest-matcher-utils

npm i https://pkg.pr.new/jest-matcher-utils@16005

jest-message-util

npm i https://pkg.pr.new/jest-message-util@16005

jest-mock

npm i https://pkg.pr.new/jest-mock@16005

@jest/pattern

npm i https://pkg.pr.new/@jest/pattern@16005

jest-phabricator

npm i https://pkg.pr.new/jest-phabricator@16005

jest-regex-util

npm i https://pkg.pr.new/jest-regex-util@16005

@jest/reporters

npm i https://pkg.pr.new/@jest/reporters@16005

jest-resolve

npm i https://pkg.pr.new/jest-resolve@16005

jest-resolve-dependencies

npm i https://pkg.pr.new/jest-resolve-dependencies@16005

jest-runner

npm i https://pkg.pr.new/jest-runner@16005

jest-runtime

npm i https://pkg.pr.new/jest-runtime@16005

@jest/schemas

npm i https://pkg.pr.new/@jest/schemas@16005

jest-snapshot

npm i https://pkg.pr.new/jest-snapshot@16005

@jest/snapshot-utils

npm i https://pkg.pr.new/@jest/snapshot-utils@16005

@jest/source-map

npm i https://pkg.pr.new/@jest/source-map@16005

@jest/test-result

npm i https://pkg.pr.new/@jest/test-result@16005

@jest/test-sequencer

npm i https://pkg.pr.new/@jest/test-sequencer@16005

@jest/transform

npm i https://pkg.pr.new/@jest/transform@16005

@jest/types

npm i https://pkg.pr.new/@jest/types@16005

jest-util

npm i https://pkg.pr.new/jest-util@16005

jest-validate

npm i https://pkg.pr.new/jest-validate@16005

jest-watcher

npm i https://pkg.pr.new/jest-watcher@16005

jest-worker

npm i https://pkg.pr.new/jest-worker@16005

pretty-format

npm i https://pkg.pr.new/pretty-format@16005

commit: c7e584f