Determine which of two nodes appears in front of the other.
The stacking order rules are fairly complex. Determining whether node A will render in front of node B involves much more than comparing the z-index
of the two nodes โ you have to consider their parents, and which of them create new stacking contexts, which in turn depends on CSS properties like opacity
, transform
, mix-blend-mode
and various others that you probably hadn't considered.
The tie-breaker, if that doesn't yield a conclusive answer, is the position in the document (with later nodes rendering in front of earlier nodes).
npm install --save stacking-order
...or grab a copy from npmcdn.com/stacking-order.
import { compare } from 'stacking-order';
const a = document.querySelector('.a');
const b = document.querySelector('.b');
const order = compare(a, b);
// -> `1` if a is in front of b, `-1` otherwise
It's entirely possible that the algorithm used here doesn't exactly match the spec. If you find a bug, please raise an issue after reading CONTRIBUTING.md. Thanks!
MIT
made by @rich_harris