This is a minimal reproduction repository for a memory leak in @testing-library/jest-dom

Issue description

Jest has a --detectLeaks flag, which causes tests to fail if there is a memory leak. Importing @testing-library/jest-dom causes a memory leak in NodeJS v20. However, in NodeJS v18 the memory leak does not occur.

How to reproduce

1. Clone this repository
2. Switch to NodeJS v20
3. Run npm install and npm run test
4. The test should fail with the message "Your test suite is leaking memory. Please ensure all references are cleaned."
5. Remove require("@testing-library/jest-dom"); from jest-setup.js
6. Rerun the test. It should pass, indicating that the memory leak is resolved.

Important notes

1. The memory leak does not occur in Node.js v18.
2. When commenting out require('aria-query'); var matchers = require('./matchers-5ae87d41.js'); and expect.extend(matchers.extensions); from ./node_modules/@testing-library/jest-dom/dist/index.js memory leak disappears. Both var matchers and require('aria-query') cause a memory leak.