Incorrect polyfill causes crash

[denke8]

Describe the bug
It's not exactly a bug on the library itself, rather a request for stronger verification.

Context:
I'm developing a widget, that is embedded into many different CMSs. There is one in particular, that has the following code:

 if (!window.requestIdleCallback) {
        window.requestIdleCallback = (cb) => {
            setTimeout(cb, 0);
        }
    }

It does not implement the interface correctly, and does not implement the cancel feature at all.

This does the following to OverlayScrollbars at this point:

• Assume the browser does not natively support requestIdleCallback
• idleSupported becomes true since wnd.requestIdleCallback is a function
• cIdle becomes undefined since cancelIdleCallback is not implemented
• the app crashes when cIdle is called (when the UI is destroyed)

To Reproduce

• Inject the above code before creating a scrollbars component
• Create a scrollbars component
• Destroy the component
• Crash happens

Environment

• OverlayScrollbars version:

  overlayscrollbars: 2.11.5
  overlayscrollbars-react: 0.5.6

• Used Operating System(s): MacOS, IOS (any)
• Used Browser(s) (with version): Safari (any) / IOS Safari (any)

Additional context
This is more of a workaround request than a bug report. What I'd like to ask is, when idleSupported is being set, either:

• Also check that typeof wnd.cancelIdleCallback === 'function' (minimal solution)
• Verify that window.requestIdleCallback is native code, perhaps by requestIdleCallback.toString() .includes('[native code]') (Imo more robust solution)

I'd be happy to contribute too, if you are okay with one of the above suggestions ...?

I know that this is not something that your library should have to do, so thank you for considering it!

[KingSora]

Good day @denke8 :)

I guess there is no way to implement a fix on your side?.. Since this is not really OverlayScrollbars specific but could and will happen to any code that uses requestIdleCallback

[denke8]

Good day @KingSora Thank you for taking a look at this! :)

I guess there is no way to implement a fix on your side?

Unfortunately the website's code is outside of my control, I can only influence the widget. We didn't manage to get through their support yet either.

Since this is not really OverlayScrollbars specific but could and will happen to any code that uses requestIdleCallback

That is correct, and I completely understand if your answer is a no. But since this is not the first incorrect implementation of a requestIdleCallback that I see out there (this one is the worse yet), and your library already is able to handle not having that browser feature as good or better than any of what I saw to date, I was hoping, maybe you'd be OK adding this extra piece of verification.

Thank you!

[denke8]

Good day @KingSora

Since the core issue is not with the library, I'll close this.

Thank you for taking a look!