fix: default pointer event pointerType to empty string instead of the string "undefined"

[tzh476]

What

Set pointerType to an empty string on synthetic click events when no pointer type was provided, instead of setting it to the string "undefined".

Why

initPointerEvent used String(pointerType). When pointerType is missing, that becomes the invalid token "undefined". Real click events can have an unset pointerType; they should never use that string.

Fixes #1291

How

Set pointerType to an empty string when it is defined.

Testing

• Added unit tests for a keyboard click as well as for the constructor

Checklist

• Tests
• Ready to be merged

Made with Cursor

[snowystinger]

Thanks for the PR. I don't think this is quite right, you're editing the initialisation of the PointerEvent, but the spec says that it should be initialised to an empty string https://w3c.github.io/pointerevents/#pointerevent-interface so it shouldn't ever be undefined.

I checked this on Chrome as well, https://jsfiddle.net/f6nLaruj/ by focusing the button, then pressing "Enter". This results in click followed by an empty string ''.

It'd be good to test the same user flow instead of directly asserting on createEvent, that's not a very helpful test as it's not something we can compare the results of against browsers. It's useful to stop a regression, but for proof for this PR, it's not accurate.

[tzh476]

Updated in 32e4155:

• Initialized pointerType to '' (empty string) when not provided/undefined, conforming to the W3C PointerEventInit specification default.
• Added tests asserting pointerType: '' on default event initialization and on keyboard-triggered click events ([Enter] on button elements).

[github-actions]

🎉 This PR is included in version 14.6.6 🎉

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