Jest: Dynamic imports don't work in nodejs

[aalexgabi]

🐛 Bug Report

Cannot dynamically import module in jest tests.

To Reproduce

Steps to reproduce the behavior:

test('dynami', async () => {
    const tenderElement = await import('mymodule');
});

Throws:

% npx jest test/dy.spec.js
(node:25196) ExperimentalWarning: The ESM module loader is experimental.
 FAIL  test/dy.spec.js
  ✕ dynami (1ms)

  ● dynami

    TypeError: A dynamic import callback was not specified.TypeError [ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING]: A dynamic import callback wa
s not specified.

      1 | test('dynami', async () => {
    > 2 |     const tenderElement = await import('mymodule');
        |                           ^
      3 | });

      at Object.<anonymous> (test/dy.spec.js:2:27)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        0.313s, estimated 1s
Ran all test suites matching /test\/dy.spec.js/i.

Expected behavior

Expected the dynamic import to work.

envinfo

% npx envinfo --preset jest
npx: installed 1 in 0.696s

  System:
    OS: Linux 5.3 Manjaro Linux
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Binaries:
    Node: 13.7.0 - /usr/bin/node
    Yarn: 1.22.0 - /usr/bin/yarn
    npm: 6.13.6 - /usr/bin/npm
  npmPackages:
    jest: ^24.9.0 => 24.9.0 

[aalexgabi]

It seems that this is a known issue: https://github.com/facebook/jest/issues/9430

Essentially the same as above, but passed as importModuleDynamically when constructing the module. Will also support jest.mock, jest.resetModules etc more cleanly, so likely to be used quite a bit.

This can also be done for vm.Script via the same option.

[SimenB]

Correct, this is blocked by #9430. For now you'll need to transpile it (using Babel, TypeScript, or something else like it)

[d3x0r]

It's not clear that there is a method that works... an alternative workaround is perhaps to use .mjs instead of .js.

[SimenB]

dynamic import has been implemented in #10620, released in 26.5.3