fix(useElementVisibility): adjust threshold to 0 to fix visibility issue with large element

[erikkkwu]

…sue with large element

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Description

fix #3305
large element cause intersectionRatio to fall below the default threshold 0.1, making elementIsVisible false (e.g., viewport height 900 / target height 9001).

Additional context

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🤖 Generated by Copilot at 65d7dfa

Added threshold option to useElementVisibility hook to support elements with zero dimensions. This option controls how much of the element's area needs to be visible before the hook reports it as visible.

🤖 Generated by Copilot at 65d7dfa

• Add threshold option to IntersectionObserver constructor to detect visibility of zero-sized elements (link)

[samuveth]

tACK

[rikzwarthoff]

@erikkkwu @antfu @samuveth, Hi guys, this parameter is now hard coded, whilst it should be passed through as an option imo. We've had issues with 0 threshold, I actually need it to be 0.1

[edtorba]

@erikkkwu @antfu @samuveth, Hi guys, this parameter is now hard coded, whilst it should be passed through as an option imo. We've had issues with 0 threshold, I actually need it to be 0.1

I had the exact same issue. As a workaround, I moved to using useIntersectionObserver. However, I am considering spinning up a PR to allow its definition via an option.

[erikkkwu]

Hello @rikzwarthoff @edtorba, I would like to inquire about the specific situations in which you encounter issues. Indeed, if you do face problems, I agree that it should be possible to turn it into an option

[rikzwarthoff]

Hi @erikkkwu, we have the following situation. A div wrapped around a table, which has multiple tbody elements, each of those tbody elements has a useElementVisibility where the scrollTarget is the div. Now the table has an after element with calculated height so you can always scroll the last tbody to the top. The first row of each tbody is sticky, my guess that the problem would the there.

I can sent you the url privately, if you would want it.