README

react-resize-aware

It does one thing, it does it well: listens to resize events on any HTML element.

react-resize-aware is a zero dependency, ~600 bytes React Hook you can use to detect resize events without relying on intervals, loops, DOM manipulation detection or CSS redraws.

It takes advantage of the resize event on the HTMLObjectElement, works on any browser I know of, and it's super lightweight.

In addition, it doesn't directly alters the DOM, everything is handled by React.

Looking for the 2.0 docs? Click here

Installation

yarn add react-resize-aware

or with npm:

npm install --save react-resize-aware

Usage

The API is simple yet powerful, the useResizeAware Hook returns a React node you will place inside the measured element, and an object containing its sizes:

import React from 'react';
import useResizeAware from 'react-resize-aware';

const App = () => {
  const [resizeListener, sizes] = useResizeAware();

  return (
    <div style={{ position: 'relative' }}>
      {resizeListener}
      Your content here. (div sizes are {sizes.width} x {sizes.height})
    </div>
  );
};

Heads up!: Make sure to assign a position != initial to the HTMLElement you want to target (relative, absolute, or fixed will work).

API

The Hook returns an array with two elements inside:

`[resizeListener, ...]` (first element)

This is an invisible React node that must be placed as direct-child of the HTMLElement you want to listen the resize events of.

The node is not going to interfer with your layouts, I promise.

`[..., sizes]` (second element)

This object contains the width and height properties, these properties are going to be null before the component rendered, and will return a number after the component rendered.

Custom `reporter`

You can customize the properties of the sizes object by passing a custom reporter function as first argument of useResizeAware.

const customReporter = target => ({
  clientWidth: target != null ? target.clientWidth : null,
});

const [resizeListener, sizes] = useResizeAware(customReporter);

return (
  <div style={{ position: 'relative' }}>
    {resizeListener}
    Your content here. (div clientWidth is {sizes.clientWidth})
  </div>
);

The above example will report the clientWidth rather than the default offsetWidth and offsetHeight.

React to size variations

For completeness, below you can find an example to show how to make your code react to size variations using React Hooks:

const App = () => {
  const [resizeListener, sizes] = useResizeAware();
  
  React.useEffect(() => {
    console.log('Do something with the new size values');
  }, [sizes.width, sizes.height]);

  return (
    <div style={{ position: 'relative' }}>
      {resizeListener}
      Your content here.
    </div>
  );
}

Usage no npm install needed!