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[Bug]: Jest doesn't run with node --loader option

See original GitHub issue

Version

27.0.6

Steps to reproduce

Example steps:

Install any loader (targos/multiloader, quibble, node-loader/core were all tried)
Run jest with node --loader @multiloader/loader --experimental-vm-modules node_modules/.bin/jest (replace loader name as you will)

Expected behavior

I expect the tests to run OR if the --loader flag in invalid I expect some kind of error message to appear and the test run to exit out.

Actual behavior

Error:

(node:44385) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
(node:44385) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time

and then the tests do not run at all, no actual error appears.

Additional context

No response

Environment

System:
    OS: macOS 11.3.1
    CPU: (16) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
  Binaries:
    Node: 14.17.4 - ~/.nvm/versions/node/v14.17.4/bin/node
    Yarn: 1.22.10 - /usr/local/bin/yarn
    npm: 6.14.14 - ~/.nvm/versions/node/v14.17.4/bin/npm
  npmPackages:
    jest: ^27.x.x => 27.0.6

Issue Analytics

State:
Created 2 years ago
Reactions:1
Comments:10 (4 by maintainers)

Top GitHub Comments

1reaction

PamMarieGxcommented, Aug 27, 2021

@sigveio thank you so much for looking into this more! The --runInBand does let the tests run, but the loader doesn’t seem to be registered properly in that case.

The use case for this specific loader is that Jest doesn’t support ESM mocking yet, but testdouble does with the loader. The intent was to use testdouble as a workaround until mocking was available for ESM in Jest. This is what mocha recommends to get around their lack of ESM mocking, and I was hoping I could get it to work with Jest, since I prefer Jest and Jest lets me watch .mjs files.

0reactions

github-actions[bot]commented, Oct 27, 2022

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs. Please note this issue tracker is not a help forum. We recommend using StackOverflow or our discord channel for questions.