Closed
Description
- I'd be willing to implement a fix
Describe the bug
Yarn 2 crashes when loading a worker file written as ES module.
To Reproduce
const {promises: {writeFile}} = require(`fs`);
await packageJsonAndInstall({});
const WORKER_PATH = './worker.mjs';
await writeFile(WORKER_PATH, `
import { isMainThread, Worker } from "worker_threads";
if (isMainThread) {
new Worker("${WORKER_PATH}");
} else {
// Worker code here
}
`)
await expect(yarn('node', WORKER_PATH))
.rejects.not.toThrow(`Must use import to load ES Module`);Environment if relevant (please complete the following information):
- Node version [e.g. 8.15.0, 10.15.1, ...] 13.7.0
- Yarn version [e.g. 2.0.0-rc1, ...] master (cae4477)
Additional context
Node.js can load script workers as well as ES modules workers (although ESM is still experimental at time of writing). It uses the same resolution algorithm as non-worker file to pick EMS loader or CJS loader. To qualify as ESM, a file is either:
- using
.mjsas extension. - using
.jsas extension and the closestpackage.jsoncontainstype=module.