fix: Null check added when resolving event's priority #31044
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Hmm, the repro you provided is overriding a global to be null. I think that shouldn't ever happen in practice, though. Is there a legitimate case in some supported browser where the event can be null as opposed to undefined? |
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@josephsavona Thanks for quick answer. Yes, indeed it shouldn't be overwritten, but in real world I have experienced that client's app somehow is overriding this and I'm injecting a script into theirs app where I'm rendering react app and it will give me this error. |
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Fair. This seems reasonable to add, but we also need a regression test. Can you add on here? |
josephsavona
requested changes
Sep 27, 2024
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@josephsavona I have added a test to cover this case. Cheers |
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Summary
I wanted to migrate from React 17 to React 18 and experienced issues with rendering when using new root API.
When
window.eventisnull,Uncaught TypeError: Cannot read properties of null (reading 'type')error can be thrown when calling render function.✅ Example with React 17 where nothing breaks and component is rendered correctly:
https://jsfiddle.net/9zg3t4mc/1/
❌ Example with React 18 where error is thrown and component is not rendered:
https://jsfiddle.net/92wtjb0g/
How did you test this change?
I run
yarn buildand then useReact-prod.jsinside fiddle that is throwing an error and with this change render is working now.