ESM Problems with Jest@26 and Node.js 14.x

Hi, I’m using jest to test my project. Trying to test a file where I import uuid results with an error:

 ● Test suite failed to run

    SyntaxError: The requested module 'uuid' does not provide an export named 'v1'

          at async Promise.all (index 0)
      at jasmine2 (node_modules/jest-jasmine2/build/index.js:228:5)

I saw @dps910 comment and I guess it’s something similar. I’m using UUID@8, node@14 and Jest@26 (and it’s freshly-supported esm modules implementation).

Jest command: node --experimental-vm-modules .\node_modules\jest\bin\jest.js The file that I’m testing imports uuid like you suggested:

import { v1 as uuidv1 } from 'uuid';
uuidv1();

It fails only when I’m testing though.

_Originally posted by @Tzahile in https://github.com/uuidjs/uuid/issues/245#issuecomment-628650062_

[pl12133]

My workaround for this was to manually map the uuid module to it’s commonJS export:

// jest.config.js
moduleNameMapper: {
    // Force module uuid to resolve with the CJS entry point, because Jest does not support package.json.exports. See https://github.com/uuidjs/uuid/issues/451
    "uuid": require.resolve('uuid'),
},

EDIT: This might not work depending on your projects dependency structure. See https://github.com/microsoft/accessibility-insights-web/pull/5421#issuecomment-1109168149 for a much better explanation.

This works and is more scoped than overriding exports conditions, but has the downside that it is essentially a silent yarn resolution; it forces every dependency chain through uuid to use whatever version of uuid happens to be hoisted, even if some chains want older versions.

[ctavan]

I have released uuid@9.0.0-beta.0 that should restore compatibility with Jest. Please try it out and let me know if it fixes the Jest interoperability (to be tested with jest@29.0.0-alpha.1).