Inline workers does not work in Edge Legacy anymore

[mpk]

• Operating System: Windows 10
• Node Version: 12.14.0
• NPM Version: 6.13.4
• webpack Version: 4.44.2
• worker-loader Version: 3.0.3

Expected Behavior

Inline worker should execute in Edge Legacy

Actual Behavior

Inline worker does not execute in Edge Legacy

Code

// webpack.config.js
let HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
	entry: './index.js',
	plugins: [new HtmlWebpackPlugin()]
};

// index.js
import TestWorker from 'worker-loader?inline=no-fallback!./worker';

let worker = new TestWorker();
console.log(worker);

// worker.js
console.log('Log from worker');

How Do We Reproduce?

The code should write "Log from worker" into the console. However, it does not work in Edge Legacy browser (tested on version 18.18363). The worker is created successfully, but its contents are not executed, so nothing gets logged into the console.

I have looked at the worker-loader code and found out that the problem is in URL.revokeObjectURL(objectURL); line in inline.js. When I commented out that line, Edge executed the worker contents. Wrapping the call in setTimeout with 1000ms delay worked as well, but that solution seems quite hacky.

This issue is not present in worker-loader 2.0.0

[alexander-akait]

Feel free to send a fix:

if (URL.revokeObjectURL) {
  URL.revokeObjectURL(objectURL);
}

Should be easy

[mpk]

No, Edge Legacy actually supports URL.revokeObjectURL, but it does not like when the Blob URL is revoked "too quickly".

[Rush]

inline workers stopped working for me after upgrading to 3.x and changing inline: true to inline: 'no-fallback'

Investigating network shows a script with contents:

importScripts('http://localhost:4000/[object%20Module]');

[alexander-akait]

@mpk Can you create reproducible test repo?

[alexander-akait]

@Rush It is not you problem, please provide reproducible test repo, I will help

[mpk]

@evilebottnawi Sure, here you go: https://github.com/mpk/worker-loader-edge

[alexander-akait]

@mpk to be honestly I can't reproduce 😕

[KallynGowdy]

I'm having a similar issue with Chrome (87.0.4280.88) and Edgium (87.0.664.55) on worker-loader v3.0.6 with webpack v5.10.0.
It is worth noting that the worker loads fine on Firefox.

Definitely seems like a race condition because if I put a breakpoint at inline.js line 31 and continue after half a second then the worker loads correctly but if I disable the breakpoint then it does not load.

In light of this, the root cause appears to actually be a Chrome bug however I haven't found anything in their bug tracker.

[Shravan-Joopally]

I could reproduce this issue consistently on IE 11. Definitely revoking the object url immediately is issue. If I tried below code its working fine.

import TestWorker from 'worker-loader?inline=no-fallback!./worker';

let tmp = URL.revokeObjectURL;
URL.revokeObjectURL = function() {};

let worker = new TestWorker();

URL.revokeObjectURL = tmp;

console.log(worker);

[alexander-akait]

Can you check revokeObjectURL is exist?

[Shravan-Joopally]

yes its there

[alexander-akait]

Weird, it should work, no errors? Can you add try/catch for revokeObjectURL and check again

[Shravan-Joopally]

yeah, no errors