Compiled code seems broken

[bvaughn]

Calling e.g. ref.current.resetAfterColumnIndex() on VariableSizeGrid seems to trigger a runtime error.

Resize the window of this Code Sandbox to repro: https://codesandbox.io/s/5ywr9ro7nn

It looks like the this context is getting messed up somehow. (this is valid but _this is undefined.)

[TrySound]

This doesn't look like a bug in compiled code. I see you use this inside of initInstanceProps which is not called with any instance. Arrow functions of course doesn't have own context.

[TrySound]

Use instance instead of this.

[bvaughn]

Didn't have time to dig into the underlying cause, just noted that the compiled code was referencing the wrong thing and wanted to leave a note for myself to fix later (or you if you beat me to it 😉)

[TrySound]

Seems like you didn't covered this case with tests. This code doesn't look correct.
https://github.com/bvaughn/react-window/blob/master/src/VariableSizeGrid.js#L406

[TrySound]

I just passed by. Didn't have this issue yet.

[bvaughn]

Fixed via 35f99db