Can't use Worker-Loader with Vuejs and Webpack - multithreading

Question

I am trying to get web workers up and running with Vue cli3 and I'm having trouble getting it to work.
I want to use the following package, worker-loader (and not vue-worker), as it looks well maintained and with more contributions.
Following their tutorial I attempted to modify webpack using the vue cli as follows:
module.exports = {
chainWebpack: config => {
config.module
.rule('worker-loader')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
.end()
}
}
which I hope should match their
{
module: {
rules: [
{
test: /\.worker\.js$/,
use: { loader: 'worker-loader' }
}
]
}
}
which can be read here (https://github.com/webpack-contrib/worker-loader). I tried to follow the documentation for vue cli3 as best I could (found here: https://cli.vuejs.org/guide/webpack.html#simple-configuration).
My component is pretty simple:
import Worker from 'worker-loader!./../../sharedComponents/equations/recurringTimeComposer.js';
<...>
watch:{
recurringPaymentReturnObj: function(newVal, oldVal){
const myWorker = new Worker;
myWorker.postMessage({ hellothere: 'sailor' });
myWorker.onmessage = (e) => {
console.log('value of e from message return', e.data);
}
}
<...>
and in my ./../../sharedComponents/equations/recurringTimeComposer.js file I have:
onmessage = function(e) {
console.log('Message received from main script: ', e.data);
// var workerResult = 'Result: ' + e.data;
// console.log('Posting message back to main script');
postMessage('hello back handsome');
close();
}
I keep getting the error message:
ReferenceError: window is not defined a162426ab2892af040c5.worker.js:2:15
After some googling I came across this post: https://github.com/webpack/webpack/issues/6642, which suggests that the best way to fix this is to add the following to webpack:
output: {
path: path.join(__dirname, 'dist'),
filename: 'bundle.js'
publicPath: 'http://localhost:3000',
globalObject: 'this'
},
After modifying my vue.config.js file I have:
module.exports = {
chainWebpack: config => {
config.module
.rule('worker-loader')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
.end()
config
.output
.path(path.join(__dirname, 'dist'))
.filename('bundle.js')
.publicPath('http://localhost:8080')
.globalObject('this')
}
}
...but still I am getting the window is not defined error.
Does anyone know what is going wrong? It seems to be a weird error in webpack.
Thanks!
EDIT: oh yeah, here is the MDN page for webworker as well: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Using_web_workers.

Answer 1

Being new to Javascript I kept coming back to this issue when trying to use web workers with VueJS. I never managed to make it work with vue-worker or worker-loader.
It is now 2020 and Google has released worker-plugin.
To use it create a module my-worker with two files index.js and worker.js.
index.js creates the module:
const worker = new Worker('./worker.js', { type: 'module' });
const send = message => worker.postMessage({
message
})
export default {
worker,
send
}
worker.js contains the logic:
import _ from 'lodash'
addEventListener("message", async event => {
let arrayToReverse = event.data.message.array
let reversedArray = _.reverse(arrayToReverse)
// Send the reversed array
postMessage(reversedArray)
});
You will also need to update your vue.config.js to use the WorkerPlugin:
const WorkerPlugin = require('worker-plugin')
module.exports = {
configureWebpack: {
output: {
globalObject: "this"
},
plugins: [
new WorkerPlugin()
]
}
};
Now you can use you worker in your components:
Import it with import worker from '#/my-worker'.
Setup a listener in the mounted() lifecycle hook with worker.worker.onmessage = event => { // do something when receiving postMessage }
Start the worker with worker.send(payload).
I set up a starter code on github. I still haven't managed to make HMR work though...

Answer 2

This works for me (note the first line):
config.module.rule('js').exclude.add(/\.worker\.js$/)
config.module
.rule('worker-loader')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
The first line excludes worker.js files, so two loaders wouldn't fight over the same js file

Answer 3

is this what you need ? Vue issue with worker-loader

Answer 4

Updating from the classic vue & webpack config, I found out that to make this one work, I needed to deactivate parallelization.
// vue.config.js
module.exports = {
parallel: false,
chainWebpack: (config) => {
config.module
.rule('worker')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
.end();
}
};

Answer 5

I tried add web worker to a vue-cli4 project, and here is what I found:
using worker-loader and make configs in chainWebpack:
HMR works fine, but sourcemap broke, it show babel transformed code.
using worker-plugin as #braincoke mentioned:
HMR broke, but sourcemap works fined. and eslint broke while suggested disable all worker js file eslint instead.
Finally, My solution is tossing vue-cli away, and embrace vite.It support worker natively, and all just go fine now. (I think upgrade webpack to v5 can solve this, but i never tried.)