overscanCount = 0? - Githubissues

bvaughn / react-window

React components for efficiently rendering large lists and tabular data

https://react-window.now.sh/

MIT License

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overscanCount = 0? #67

Closed stnwk closed 5 years ago

stnwk commented 6 years ago

Hi :)

I was wondering whether you'd consider to allow actually setting overscanCount value of 0. Currently the required minimum is 1 to enable tabbing, which is completely understandable.

However, I am currently working on a case where the rendered items are rather expensive and tabbing is not important/disabled on purpose so I'd really appreciate a way to override this.

Thanks for your consideration!

bvaughn commented 6 years ago

Hi :)

I think I understand why you'd want this ability, although I also think it's an edge case and in nearly all cases– forcing an overscan for accessibility is the "right" thing to do.

I don't really have the time to implement this, but if you'd be interested in submitting a PR with all of the following, I'd probably be willing to merge it:

Update both list and grid components with a DEV-only warning if the overscan prop is ever set to 0 saying that it's bad for accessibility. (This warning should go in validateSharedProps and be wrapped in the process.env.NODE_ENV !== 'production' check so as not to bloat the production bundle.)
Update any affected tests to ensure that the default behavior is not changed and the new DEV warning is logged if overscan count is ever set to zero.

stnwk commented 6 years ago

Thanks!

I'll take care of this then, expect a PR when your back from your holidays :)

(not being creepy, just following you on twitter haha)

Enjoy your family time!

bvaughn commented 6 years ago

Thank you! 😄 Sounds good to me.

stnwk commented 5 years ago

Full disclosure: I ended up not needing this particular option, so there's no need for me at this time to implement it.

Still, thanks again for your time & thoughts!

itdhsc commented 3 years ago

This was exactly the feature we needed right now. Our background: We have a default height for each row and the actual height is calculated after the data is fetched from the server. The user has the possibility to scroll to a specific item automatically and display it at 'start'.

The problem: If the item in the overscan area before the scrollToItem has a height greater than the default height the item that should be aligned at 'start' is pushed down by the height difference after the data was fetched from the server.