Fix: TypeError: file.replace is not a function

[purplecandy]

Fixes issue #3890 which happens while developing on Linux.

Chowkidar returns an instance of FSWatcher which may or may not produce a Stat object with change events instead of just a string. The issue is easily reproducible on Linux systems.

[squidfunk]

Thanks for the PR. This sounds like something that should be fixed upstream, or is it documented behavior? Have you checked the issue tracker of chokidar whether this is a known issue?

[purplecandy]

There are no open issues related to it as it's not a bug. It is just that the underlying watch event implementation uses different utilities depending on the OS. The only thing I found related to it on chokidar was this

[squidfunk]

Thanks again! Okay, so after investigating, I can say with confidence that the problem is triggered by RxJS, and not Chokidar. If there's more than one argument that is passed to the handler, RxJS emits an array, otherwise the first argument. However, we can just use the resultSelector to always return the first argument. Fixed in and superseded by 26de756.