react-measure

What is react-measure?

The react-measure package is a React component that allows you to measure the dimensions and position of a DOM element. It provides a declarative way to get the size and position of elements, which can be useful for responsive design, animations, and other dynamic UI behaviors.

What are react-measure's main functionalities?

Measure Dimensions

This feature allows you to measure the width and height of a DOM element. The `Measure` component wraps around the element you want to measure, and the `onResize` callback updates the state with the new dimensions whenever the element is resized.

import React from 'react';
import Measure from 'react-measure';

class MyComponent extends React.Component {
  state = {
    dimensions: {
      width: -1,
      height: -1
    }
  };

  render() {
    return (
      <Measure
        bounds
        onResize={(contentRect) => {
          this.setState({ dimensions: contentRect.bounds });
        }}
      >
        {({ measureRef }) => (
          <div ref={measureRef} style={{ width: '100%' }}>
            <p>The width of this element is {this.state.dimensions.width}px</p>
            <p>The height of this element is {this.state.dimensions.height}px</p>
          </div>
        )}
      </Measure>
    );
  }
}

export default MyComponent;

Measure Position

This feature allows you to measure the position (top and left) of a DOM element. The `Measure` component wraps around the element you want to measure, and the `onResize` callback updates the state with the new position whenever the element is resized.

import React from 'react';
import Measure from 'react-measure';

class MyComponent extends React.Component {
  state = {
    position: {
      top: -1,
      left: -1
    }
  };

  render() {
    return (
      <Measure
        bounds
        onResize={(contentRect) => {
          this.setState({ position: contentRect.bounds });
        }}
      >
        {({ measureRef }) => (
          <div ref={measureRef} style={{ position: 'relative' }}>
            <p>The top position of this element is {this.state.position.top}px</p>
            <p>The left position of this element is {this.state.position.left}px</p>
          </div>
        )}
      </Measure>
    );
  }
}

export default MyComponent;

Other packages similar to react-measure

react-resize-detector

react-resize-detector is a lightweight package that provides a higher-order component and a hook to detect resize events on a DOM element. It is similar to react-measure in that it allows you to measure the dimensions of an element, but it does not provide as many detailed measurements (e.g., position).

react-use-measure

react-use-measure is a React hook that allows you to measure the size and position of a DOM element. It is similar to react-measure but uses hooks instead of a component-based API, making it more suitable for modern React applications that prefer hooks.

react-sizeme

react-sizeme is a higher-order component that makes it easy to measure the size of a component. It is similar to react-measure in that it provides dimensions, but it is more focused on providing a simple API for measuring size without additional features like position measurement.

README

React Measure

Compute measurements of React components. Uses resize-observer-polyfill to detect changes of an element and return the new dimensions.

Install

yarn add react-measure

npm install react-measure --save

<script src="https://unpkg.com/react-measure/dist/react-measure.js"></script>
(UMD library exposed as `Measure`)

Measure Component

Wrap any child component and calculate its client rect.

Props

client: PropTypes.bool

Adds the following to contentRect.client returned in the child function.

clientTop, clientLeft, clientWidth, and clientHeight.

offset: PropTypes.bool

Adds the following to contentRect.offset returned in the child function.

offsetTop, offsetLeft, offsetWidth, and offsetHeight.

scroll: PropTypes.bool

Adds the following to contentRect.scroll returned in the child function.

scrollTop, scrollLeft, scrollWidth, and scrollHeight.

bounds: PropTypes.bool

Uses getBoundingClientRect to calculate the element rect and add it to contentRect.bounds returned in the child function.

margin: PropTypes.bool

Uses getComputedStyle to calculate margins and add it to contentRect.margin returned in the child function.

innerRef: PropTypes.func

Use this to access the internal component ref.

onResize: PropTypes.func

Callback invoked when either element width or height have changed.

children: PropTypes.func

Children must be a function. Will receive the following object shape:

• measureRef: must be passed down to your component's ref in order to obtain a proper node to measure

• measure: use to programmatically measure your component, calls the internal measure method in withContentRect

• contentRect: this will contain any of the following allowed rects from above: client, offset, scroll, bounds, or margin. It will also include entry from the ResizeObserver when available.

Example

import Measure from 'react-measure'
import classNames from 'classnames'

class ItemToMeasure extends Component {
  state = {
    dimensions: {
      width: -1,
      height: -1
    }
  }

  render() {
    const { width, height } = this.state.dimensions
    const className = classNames(
      (width < 400) && 'small-width-modifier'
    )

    return (
      <Measure
        bounds
        onResize={(contentRect) => {
          this.setState({ dimensions: contentRect.bounds })
        }}
      >
        {({ measureRef }) =>
          <div ref={measureRef} className={className}>
            I can do cool things with my dimensions now :D

            { (height > 250) &&
              <div>Render responsive content based on the component size!</div>
            }
          </div>
        }
      </Measure>
    )
  }
}

withContentRect(types) HoC

A higher-order component that provides dimensions to the wrapped component. Accepts types, which determines what measurements are returned, similar to above. Then returns a function to pass the component you want measured.

Pass an array or single value of either client, offset, scroll, bounds, or margin to calculate and receive those measurements as the prop contentRect in your wrapped component. You can also use the measure function passed down to programmatically measure your component if you need to. And finally, remember to pass down the measureRef to the component you want measured.

Passes down the same props as the Measure child function above, measureRef, measure, and contentRect.

Fun fact, the Measure component is a thin wrapper around withContentRect. Just check the source. This means your wrapped component will accept the same props as Measure does 😊

Example

import { withContentRect } from 'react-measure'

const ItemToMeasure = withContentRect('bounds')(({ measureRef, measure, contentRect }) => (
  <div ref={measureRef}>
    Some content here
    <pre>
      {JSON.stringify(contentRect, null, 2)}
    </pre>
  </div>
))

Run Example

clone repo

git clone [e-mail]:souporserious/react-measure.git

move into folder

cd ~/react-measure

install dependencies

npm install

run dev mode

npm run dev

open your browser and visit: http://localhost:8080/