Contains 4 different implementations of a scrollable table showing Eurovision 2019 Grand Final results.
Some of them including "Frozen" (spreadsheet-like) header-footer-starter-ender, implemented without javascript, but CSS sticky only!
I hope the different implementations will help understand better the topics separately. (As they did for me)
The most interesting one is WithReactWindowAndSticky, which is a sophisticated combination of react-window (well a slightly patched version ATM) CSS grid layout, and CSS sticky.
There is no React magic - It can be implemented in a similar manner with any FW/vanilla code.
I chose hard-coded cell size of 100x100 cell for simplicity,
But i don't see any blocker to implement it with even variable rows/columns, and multiple frozen rows/columns.
I will probably add a variant with ability to remove rows/columns.
It's our only!(?*) api to tell the browser that the scrolling and positioning of an element should be synced in a way:
- The browser can optimize it in the rendering pipeline
- Scrolling happens in the compositor (or close to it in the pipeline),
And only after the scroll have happened, scroll handlers are called. that's why syncing scrollable areas using js always feels bad. Even if your scroll handler is super slim. - Minimal code - When you figure out the layout - you just add it
[*] Until houdini animationworklet are available and widely supported
It's all about tradeoffs, legacy, and flexibility. Other similar table/spreadsheet-like grids are using a combination of nested/multiple scrollable areas, and scrolling them together. To avoid the sync lag due to the late-scroll-event, you will see some of them disabling native scroll, or scrolling empty big surface listening to the events, and scrolling the actually content using JS. It is an overhead, and you might loose some of the native scrolling behavior like scrollsnap, momentum, overscroll, and there's many places to make mistakes and kill performances and UX. BUT you get endless flexibility layout-wise!.
Some notable examples:
- https://www.ag-grid.com/example.php#/
- Google spreadsheet (the visual stuff are rendered into canvas but they hold also DOM cells for events!)
- https://bvaughn.github.io/react-virtualized/#/components/ScrollSync
- https://drafts.css-houdini.org/css-animationworklet/ houdini is not practical yet, but its good to read about it.
- https://developer.mozilla.org/en-US/docs/Web/CSS/contain to be widely supported.
The code might look now simple and clear, But it took me many mistakes, frustrations and iterations to bring it to this state, But i'm sure it can get even better!
- Edge >= 16
- And all rest :)
Scrollsnap included ;)
PS: i'm using yarn here.
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