react-contains-node

Check whether a DOM element is an ancestor of another element in the React Fiber tree.

Unlike Element.contains(), this also works across React portals.

Installation

npm install react-contains-node

Usage

import {unstable_containsNode} from 'react-contains-node';

const isInside = unstable_containsNode(parentElement, childElement);

console.log(isInside);

Why?

Element.contains() checks the DOM tree:

parentElement.contains(childElement);

unstable_containsNode() checks the React Fiber tree, making it useful when React portals are involved.

Note

This package relies on React's internal Fiber properties (__reactFiber$...) and may break with future React versions.