react-space-observer v0.0.3

<SpaceObserver>

A ResizeObserver react component with polyfill support

Getting Started

Add react-space-observer to your project using yarn or npm

yarn add react-space-observer

npm install react-space-observer

Use the SpaceObserver to wrap your component and report size/geometry changes

import SpaceObserver from "react-space-observer"

...
<SpaceObserver>
  {({ width, height, x, y, top, right, bottom, left }) => (
    // render your observed component here
  )}
</SpaceObserver>
...

Example

Let's use a SpaceObserver to change a component style at a certain width:

<SpaceObserver>
  {({ width }) => (
    <div
      style={{
        borderRadius: ".2rem",
        padding: "2rem",
        color: "white",
        backgroundColor: width >= 568 ? "dodgerblue" : "firebrick",
      }}
    >
      Hello, World
    </div>
  )}
</SpaceObserver>

As the component's geometry changes, the width is reported back and we are given a chance to conditionally render. Above, we changed the background color from red to blue.

How does it work?

This is a decoration around ResizeObserver. A ponyfill is used if ResizeObserver is not present. Also, only one ResizeObserver instance is stored in memory. This way, multiple observed elements can exist on a page without any additional overhead.