Fix "ReferenceError: self is not defined" (#4593)

[NameFILIP]

Fixes #4593

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[kkaefer]

The file src/util/browser/window.js is specifically intended for being used in a browser. There's a non-browser version in src/util/window.js, which is used by default. Instead of altering the browser-only version, modify your setup to avoid directly including the browser-specific version. Some bundlers read the browsers key in our package.json which specifies browser-specific file replacements. If you're building a bundle for use in Node.js, you should ignore these files.

[NameFILIP]

In my case, I'm building a bundle to be used on the frontend, but the build process is happening in Node.

@kkaefer what is the downside of writing resilient code like this? It'll still work in the browser and in addition, will not crash the node environment (while being imported, not used). Look how many people are complaining about it: #4593