jest-cli-detect-memory-leaks.md

Note: for Jest to detect a memory leak and throw an error both arguments are required i.e. detectLeaks and logHeapUsage.

10:45 nestjs-cats (master) ✗ yarn test --detectLeaks --logHeapUsage
yarn run v1.17.3
$ jest --detectLeaks --logHeapUsage
 PASS  src/auth/auth.controller.spec.ts (61 MB heap size)
 PASS  src/cats/cats.service.spec.ts (61 MB heap size)
 PASS  src/app.controller.spec.ts (61 MB heap size)
 FAIL  src/cats/cats.controller.spec.ts
  ● Test suite failed to run

    EXPERIMENTAL FEATURE!
    Your test suite is leaking memory. Please ensure all references are cleaned.

    There is a number of things that can leak memory:
      - Async operations that have not finished (e.g. fs.readFile).
      - Timers not properly mocked (e.g. setInterval, setTimeout).
      - Keeping references to the global scope.

      at ../node_modules/@jest/core/build/TestScheduler.js:257:24
      at asyncGeneratorStep (../node_modules/@jest/core/build/TestScheduler.js:131:24)
      at _next (../node_modules/@jest/core/build/TestScheduler.js:151:9)
      at ../node_modules/@jest/core/build/TestScheduler.js:156:7
      at ../node_modules/@jest/core/build/TestScheduler.js:148:12
      at onResult (../node_modules/@jest/core/build/TestScheduler.js:271:25)

 PASS  src/cats/cats.controller.e2e-spec.ts (72 MB heap size)
 PASS  src/auth/auth.service.spec.ts (77 MB heap size)

Test Suites: 1 failed, 5 passed, 6 total
Tests:       5 passed, 5 total
Snapshots:   0 total
Time:        2.338s
Ran all test suites.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.