TypeError: Class extends value #<Object> is not a constructor or null

[cyberprophet]

new google.maps.plugins.loader.Loader(loaderOptions).loadCallback(error =>
{
    . . .
}

Receive this error message "TypeError: Class extends value # is not a constructor or null" in the Code section below while executing the code above.

 _.Xh(ok.prototype, om);
    var Qga = class extends Event {
        constructor() {
            super("gmp-zoomchange")
        }
    }

When I tracked down the error message, I found the following code.

https://maps.googleapis.com/maps/api/js?libraries=drawing%2Cgeometry%2Cplaces%2Cvisualization%2Ccore%2Cmarker&key={apiKey}&callback=google.maps.__ib__

Maybe it happens in the process of importing libraries, can you tell me why?

I think I've had a similar problem with the version going up before.

[cyberprophet]

I found the cause and solved it.

I realized that when using JS, I should pay attention to global variable names.