How do I, from my objective C cocoa app code, invoke javascript in my WKWebView's page and get a return value without having to over complicate my app and account for other events being processed in between the call to javascript and after it's done? Is this not implemented? I've looked all over the internet and this seems like a highly requested feature with no solution. I understand there may be different processes involved, but process synchronization is done all of the time and doesn't seem like a real technical barrier at least in theory (though I'm not sure what the underlying codebase looks like and what it'd take to get there).
Alternative to get to the same problem's solution: before calling evaluateJavaScript, is there a way to disable other events from being concurrently processed until my completionHandler so that I can resume processing events and achieve the same effect? I don't have a depth of knowledge of NSRunLoops, so let me know if that question is exposing some misunderstanding.