[react-aria] useTextField returns onBlur null instead of undefined

[DeLm0re]

🐛 Bug Report

I do not know if this is intentional or not, but I think there is an issue with the useTextField hook in react-aria.
All event handlers returned are set to undefined when not defined except onBlur which is returned as null.

At first, it does not seem worrying, but when it comes to mergeProps things become a little more spicy.
In fact, when you try to merge props coming from react-aria with props coming for on another library (react-number-format in my case) then mergeProps results in onBlur defined as null so when activated, it prompts an error in console.

onBlur is not a function

I do not know if it is a constraint in the library code but it would be great if onBlur was returned as undefined. Plus it makes more sense considering all other handlers work like that.

💻 Code Sample

https://codesandbox.io/s/condescending-parm-s6wufv?file=/src/App.tsx

🌍 Your Environment

MacOs
React 18.2
With and without Vite 4.0.1

[reidbarber]

Looks like something we can fix here:

react-spectrum/packages/@react-aria/interactions/src/useFocus.ts

Lines 77 to 78 in 3155e4d

	onFocus: (!isDisabled && (onFocusProp || onFocusChange || onBlurProp)) ? onFocus : undefined,
	onBlur: (!isDisabled && (onBlurProp || onFocusChange)) ? onBlur : null

We are incrementally updating our files to support typescript strict mode, so I think we would have caught this in the process eventually. Feel free to open a PR if you'd like, otherwise it should get fixed eventually.

[DeLm0re]

@reidbarber Thanks for the reply & the explanation.

For the moment it is not an emergency as we found multiple workarounds. However in order to keep the code clear and concise, it would be great if this is fixed as soon as possible.

I will look into opening a PR

[snowystinger]

I've actually made this change here #3801
It was causing an issue with mergeProps for us as well #3801

[DeLm0re]

@snowystinger Awesome 👍