ckeditor
ERR_REQUIRE_ESM with Vitest when using ckeditor5-react and ckeditor5-build-classic
Hey,
When trying to run tests using Vitest and React Testing Library, I stumble on to the following error:
Error: require() of ES Module /workspaces/workspace/node_modules/.pnpm/@[email protected]/node_modules/@ckeditor/ckeditor5-watchdog/src/index.js from /workspaces/workspace/node_modules/.pnpm/@[email protected]_@[email protected]_@ckeditor+ckeditor5-editor-mu_u4cc4mpjbdj7ukcuf4x6qwbloa/node_modules/@ckeditor/ckeditor5-react/dist/index.js not supported.
Instead change the require of /workspaces/workspace/node_modules/.pnpm/@[email protected]/node_modules/@ckeditor/ckeditor5-watchdog/src/index.js in /workspaces/workspace/node_modules/.pnpm/@[email protected]_@[email protected]_@ckeditor+ckeditor5-editor-mu_u4cc4mpjbdj7ukcuf4x6qwbloa/node_modules/@ckeditor/ckeditor5-react/dist/index.js to a dynamic import() which is available in all CommonJS modules.
❯ node_modules/.pnpm/@[email protected]_@[email protected]_@ckeditor+ckeditor5-editor-mu_u4cc4mpjbdj7ukcuf4x6qwbloa/node_modules/@ckeditor/ckeditor5-react/dist/index.js:5:122
This is with the latest version of ckeditor5-react and ckeditor5-build-classic. This did work with ckeditor5-build-classic version 39.0.2, but with the latest version there seems to be issues.
A minimal StackBlitz implementation where the error can be reproduced can be found here - just let StackBlitz install the dependencies and run npm run test
While we have migrated the editor to ESM, our framework integrations are still UMD bundles that use require(), which seems to cause this problem. Support for require()-ing ESM was added in Node 22, but migrating this package to ESM should fix this issue for all supported Node versions.
As we plan to release a new major soon (adding support for React 19), we may use this opportunity to also migrate to ESM.
