If you’ve ever worked with a multi-page React app, you will invariably run into the dreaded warning in your console:
Warning: Can't perform a React state update on an unmounted component.
The most common cause of this warning is when a user kicks off an asynchronous request, but leaves the page before it completes. I especially wanted to know how to do this with hooks, because hooks are awesome.
I wanted to know how to avoid this classic React warning - here’s my solution.
To explain the above code snippet, imagine we have a sample component that simply displays a counter, and a button to increment the counter.
When we click the button, it fires off
someLongRunningProcess() - this could be a backend operation or whatever. Use your imagination.
someLongRunningProcess() has completed, we make sure we’re still mounted via the
componentIsMounted variable! If the component is still mounted, we can modify the state, no problem. If it’s not mounted - hey, that’s alright, we won’t touch the state.
This will dodge that nasty React warning! Have fun!