resize-observer

ResizeObserver component for React.

Purpose

Get notifications when an in the page changes its size.

The change in size can have any source - layout changes, DOM changes, browser resize - etc. The source is not important.

The ResizeObserver API is a performant way of getting updates on size changes.

Warning! Only works if the global ResizeObserver is available. (As of January 2018 only Chrome >= 64 ships it natively.) You could use a polyfill to ensure it's available.

Install

$ npm install @rb/resize-observer --save

# or

$ yarn add @rb/resize-observer

Usage

This component can be nested inside any parent component, and will notify when the node of the parent component changes its size.

import React from 'react';
import { render } from 'react-dom';

import ResizeObserver from '@rb/resize-observer';

const App = () => {
  return (
    <div style={{ width: '50vw', border: '1px solid red' }}>
      This element has width: 50vw, so resize the browser window to get
      notifications in the console
      <ResizeObserver
        onResize={({ width, height }) => {
          console.log({ width, height });
        }}
      />
    </div>
  );
};

render(<App />, document.getElementById('root'));

Props

• onResize: (contentRect) - you can specify an onResize function prop, which will be called with the contentRect passed by the native ResizeObserver API. You can destructure this to {width, height}

License

MIT