CodeMirror 6 homepage:


As part of the upgrade to CodeMirror 6, CodeMirror now uses an asset bundler, so during development you'll need to run a script to assemble the frontend assets.

Use of CodeMirror 6 is controlled by the wgCodeMirrorV6 configuration setting, or by passing in cm6enable=1 in the URL query string.

You can find the v6 frontend source files in src/, the compiled sources in resources/dist/, and other frontend assets managed by ResourceLoader in resources/*.


NOTE: Consider using Fresh to run these tasks.

  • npm install to install dependencies.
  • npm start to run the bundler in watch mode, reassembling the files on file change. You'll want to keep this running in a separate terminal during development.
  • npm run build to compile the production assets. You must run this step before sending the patch or CI will fail (so that sources and built assets are in sync).
  • npm run doc to generate the API documentation.
  • npm test to run the linting tools, JavaScript unit tests, and build checks.
  • npm run test:lint for linting of JS/LESS/CSS.
  • npm run test:lint:js for linting of just JavaScript.
  • npm run test:lint:styles for linting of just Less/CSS.
  • npm run test:i18n for linting of i18n messages with banana-checker.
  • npm run test:unit for the new Jest unit tests.
  • npm run selenium-test for the Selenium tests.
  • Older QUnit tests are in resources/mode/mediawiki/tests/qunit/. These have been replaced and will be removed after the CodeMirror 6 upgrade.

CodeMirror 6 change log