Web Worker - Jest - Cannot use 'import.meta' outside a module - reactjs

Question

I'm working on a nextjs 10.1.3 built-in web application. We implemented a web worker to boost up the performance in one of the pages and the plan is to continue adding more workers; also, all the code is properly unit tested, and using the worker-loader in previous webpack versions (4th and below) we were able to test it.
With the new webpack 5 version, the worker-loader plugin is not needed anymore; instead, the way to load a web worker using the new version is new Worker(new URL("#/workers/task.worker.js", import.meta.url));.
Doing it this way, my code is working as expected with npm build && npm start; however, when I try to add the respective unit tests I got the following error: Cannot use 'import.meta' outside a module and everything happens because of the import.meta.url used to add the location of the worker in the browser.
I read many posts on the web regarding babel but I want to get away from that option. Is there any other option to mock the import.meta.url with jest?
Any help will be very welcome. This is the current configuration.
package.json
{
...
"#babel/core": "^7.8.6",
"next": "^10.1.3",
"react": "^16.13.0",
"webpack": "^5.37.1"
"devDependencies": {
...
"enzyme": "^3.11.0",
"enzyme-adapter-react-16": "^1.15.2",
"jest": "^24.9.0",
"jest-cli": "^25.1.0",
...
}
...
}
next.config.js
const {
...
} = process.env;
const basePath = "";
const COMMIT_SHA = [];
const { parsed: localEnv } = require("dotenv").config();
const webpack = require("webpack");
const withBundleAnalyzer = require("#next/bundle-analyzer")({
enabled: process.env.ANALYZE === "true",
});
const nextConfig = {
env: {
NEXT_PUBLIC_COMMIT_SHA: COMMIT_SHA,
},
images: {
domains: [
"...",
],
},
future: {
webpack5: true,
},
productionBrowserSourceMaps: true,
trailingSlash: true,
reactStrictMode: true,
webpack: (config, options) => {
if (localEnv) {
config.plugins.push(new webpack.EnvironmentPlugin(localEnv));
} else {
config.plugins.push(new webpack.EnvironmentPlugin(process.env));
}
config.module.rules.push({
test: /\.(eot|woff|woff2|ttf|svg|png|jpg|gif)$/,
use: {
loader: "url-loader",
options: {
limit: 100000,
name: "[name].[ext]",
},
},
});
config.output = {
...config.output,
chunkFilename: options.isServer
? `${options.dev ? "[name]" : "[name].[fullhash]"}.js`
: `static/chunks/${options.dev ? "[name]" : "[name].[fullhash]"}.js`,
publicPath: `/_next/`,
globalObject: `(typeof self !== 'undefined' ? self : this)`,
};
config.plugins.push(new webpack.IgnorePlugin(/pages.*\/__tests__.*/));
config.plugins.push(
new options.webpack.DefinePlugin({
"process.env.NEXT_IS_SERVER": JSON.stringify(
options.isServer.toString()
),
})
);
return config;
},
};
module.exports = withBundleAnalyzer(nextConfig);
The useEffect worker
useEffect(() => {
if (pageData.data?.length) {
workerRef.current = new Worker(new URL("#/workers/task.worker.js", import.meta.url));
workerRef.current.addEventListener("message", result => {
if (result.error) {
setWorkerError();
} else {
updateData(result.data);
}
});
const ids = pageData.data.map(store => store.id);
workerRef.current.postMessage(ids);
} else {
setNoDataFound();
}
return () => {
workerRef.current && workerRef.current.terminate();
};
}, []);
jest.config.js
module.exports = {
moduleDirectories: ["node_modules", "src", "static", "store"],
modulePathIgnorePatterns: [
"<rootDir>/node_modules/prismjs/plugins/line-numbers",
],
testPathIgnorePatterns: [
"<rootDir>/src/components/component-library",
"<rootDir>/.next",
"jest.config.js",
"next.config.js",
],
collectCoverageFrom: [
"**/src/**",
"**/store/**",
"**/pages/**",
"!**/__tests__/**",
"!**/node_modules/**",
"!**/component-library/**",
],
testEnvironment: "node",
collectCoverage: true,
verbose: false,
automock: false,
setupFiles: ["./setupTests.js"],
moduleNameMapper: {
"#/components/(.*)$": "<rootDir>/src/components/$1",
"#/functions/(.*)$": "<rootDir>/src/components/functions/$1",
"#/services/(.*)$": "<rootDir>/src/components/services/$1",
"#/workers/(.*)$": "<rootDir>/src/components/workers/$1",
"#/scripts(.*)$": "<rootDir>/src/scripts/$1",
"#/src(.*)$": "<rootDir>/src/$1",
"#/__mocks__(.*)$": "<rootDir>/__mocks__/$1",
"#/pages(.*)$": "<rootDir>/pages/$1",
"#/store(.*)$": "<rootDir>/store/$1",
"\\.(css|less)$": "<rootDir>/__mocks__/styleMock.js",
},
coveragePathIgnorePatterns: ["/node_modules/"],
coverageThreshold: {
global: {
branches: 67,
functions: 66,
lines: 73,
statements: 72,
},
},
runner: "groups",
extraGlobals: [],
testTimeout: 10000,
};

Answer 1

In my setup (typescript + ts-jest) I prepended the following node option to make it work:
NODE_OPTIONS=--experimental-vm-modules
Reference can be found here: https://jestjs.io/docs/ecmascript-modules