fix(jest-config): add mjs and cjs to default moduleFileExtensions config

[F3n67u]

Summary

fix #12237

Test plan

test locally, see below:

node ~/dev/jest/packages/jest-cli/bin/jest.js         
 PASS   Sample Test Suite  tests/test-suites/sample-suite.mjs
  ✓ hello world (2 ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        0.658 s, estimated 1 s
Ran all test suites.

[SimenB]

We should add CJS as well 🙂

[F3n67u]

We should add CJS as well 🙂

@SimenB done.

[SimenB]

why this?

[F3n67u]

transform.test.ts is fail when including mjs in the extension list.

$ ./packages/jest/bin/jest.js '/Users/feng/dev/jest/e2e/__tests__/transform.test.ts'
transform-esm-runner
      ✕ runs test with native ESM (618 ms)
    transform-esm-testrunner
      ✕ runs test with native ESM (868 ms)

  ● on node >=12.17.0 › transform-esm-runner › runs test with native ESM


          Can't parse JSON.
          ERROR: SyntaxError Unexpected end of JSON input
          STDOUT: 
          STDERR: /Users/feng/dev/jest/e2e/transform/transform-esm-runner/runner.mjs:8
    import testResult from '@jest/test-result';
    ^^^^^^

    SyntaxError: Cannot use import statement outside a module

      146 |     };
      147 |   } catch (e: any) {
    > 148 |     throw new Error(
          |           ^
      149 |       `
      150 |       Can't parse JSON.
      151 |       ERROR: ${e.name} ${e.message}

      at Module._compile (node_modules/pirates/lib/index.js:135:24)
          
      at json (e2e/runJest.ts:148:11)
      at Object.<anonymous> (e2e/__tests__/transform.test.ts:326:30)

  ● on node >=12.17.0 › transform-esm-testrunner › runs test with native ESM

    expect(received).toMatch(expected)

    Expected pattern: /PASS/
    Received string:  "FAIL __tests__/add.test.js
      ● Test suite failed to run·
        /Users/feng/dev/jest/e2e/transform/transform-esm-testrunner/test-runner.mjs:7
        import testResult from '@jest/test-result';
        ^^^^^^·
        SyntaxError: Cannot use import statement outside a module·
          at Module._compile (../../../node_modules/pirates/lib/index.js:135:24)·
    Test Suites: 1 failed, 1 total
    Tests:       0 total
    Snapshots:   0 total
    Time:        0.258 s
    Ran all test suites."

      344 |       });
      345 |
    > 346 |       expect(stderr).toMatch(/PASS/);
          |                      ^
      347 |       expect(json.success).toBe(true);
      348 |       expect(json.numPassedTests).toBe(1);
      349 |     });

      at Object.toMatch (e2e/__tests__/transform.test.ts:346:22)

Test Suites: 1 failed, 1 total
Tests:       2 failed, 20 passed, 22 total
Snapshots:   5 passed, 5 total
Time:        42.588 s, estimated 59 s
Ran all test suites matching /\/Users\/feng\/dev\/jest\/e2e\/__tests__\/transform.test.ts/i.

[F3n67u]

pirate just hijack require, .mjs is es module, so we should filter out .mjs extension when we addHook

[F3n67u]

if we override Module._extensions[".mjs"], then require('test-runner.mjs') will not throw ERR_REQUIRE_ESM error but instead will an Cannot use import statement outside a module error will throw when pirates call Module._compile.

nodejs source code:

https://github.com/nodejs/node/blob/8a96ff7e545041dbf08483b4d512eefb488f0479/lib/internal/modules/cjs/loader.js#L978-L980

[F3n67u]

I added some comments to make the filter mjs extension's intention more clearer.

[SimenB]

thanks!

[SimenB]

https://github.com/facebook/jest/releases/tag/v28.0.0-alpha.8

[github-actions]

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