Browser JS: One library might use the `WindowDispatcher` from another library and fail

[odzhychko]

Describe the bug

When using multiple independent libraries in JS Browser, that each bundle Kotlinx Coroutines, one of them might fail because it tries to use the WindowDispatcher created by the other.

In the browser, the WindowDispatcher is created once and stored on the global window object as window.coroutineDispatcher

kotlinx.coroutines/kotlinx-coroutines-core/js/src/Window.kt

Lines 12 to 15 in 6e92c23

	public fun Window.asCoroutineDispatcher(): CoroutineDispatcher =
	@Suppress("UnsafeCastFromDynamic")
	asDynamic().coroutineDispatcher ?: WindowDispatcher(this).also {
	asDynamic().coroutineDispatcher = it

But the WindowDispatcher from one library might not work with the WindowDispatcher from the other because the function names got minified differently.

Provide a Reproducer

A sample project with instructions can be found in https://github.com/odzhychko/multiple-js-libs-with-coroutines

Thoughts

What would be the downsides to storing the WindowDispatcher on a static field instead, like in a classical singleton?
The property window.coroutineAnimationQueue might have the same issues as window.coroutineDispatcher.

[Demenus]

I have managed to workaround this issue using just webpack and one string replacement plugin

To be honest it has been tested just with version 1.8.0, not sure if this will break in the future

At first I have used this module

dependencies {
    implementation(devNpm("string-replace-loader", "3.1.0"))
}

However there are a lot of plugins for wepack related with string replacements

Later on the webpack.config.d/webpack-config.js

config.module = {
    rules: [
        {
            test: /\.js$/,
            loader: 'string-replace-loader',
            options: {
                search: 'coroutineDispatcher',
                replace: '<some identifier here>CoroutineDispatcher',
                flags: 'g'
            }
        }
    ]
}

The trick is to have different names for the coroutineDispatcher on every library you are creating