React Measure

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

Install

npm install react-measure --save

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

Codepen Demo

Live Demo

Example Usage w/ state

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
        onMeasure={(dimensions) => {
          this.setState({dimensions})
        }}
      >
        <div 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>
    )
  }
}

Example Usage w/ child function

import Measure from 'react-measure';

const ItemToMeasure = () => (
  <Measure>
    { dimensions =>
      <div>
        Some content here
        <pre>
          {JSON.stringify(dimensions, null, 2)}
        </pre>
      </div>
    }
  </Measure>
)

Props

whitelist: PropTypes.array

Provide a list of properties that determine when onMeasure should fire. Accepts any of the following properties ['width', 'height', 'top', 'right', 'bottom', 'left']

blacklist: PropTypes.array

Like above, but will not fire onMeasure for the specified properties.

includeMargin: PropTypes.bool

Whether or not to include margins in calculation. Defaults to true.

useClone: PropTypes.bool

Tries to give the most accurate measure by cloning the element and measuring it. Use if your item is hidden or you want to determine what a new dimension will be.

cloneOptions: PropTypes.Object

Passes clone options to getNodeDimensions.

shouldMeasure: PropTypes.bool

Determines whether or not a measurement should occur. Useful if you only need to measure in certain cases.

onMeasure: PropTypes.func

Callback when the component dimensions have changed. Receives the new dimensions of your component.

Good to knows

To help avoid layout thrashing, use the prop blacklist to ignore specific values and stop firing a render to check the DOM for changes. Likewise you can use whitelist to choose only the ones you need to check.

Margins from hell. If your element is not calculating width or height properly it could be due to a margin hanging outside of its container. To get a true measurement, make sure to not have any hanging margins, in some cases a padding of 1px added to the container will fix this. See the stack overflow answers here for more tricks .

Run Example

clone repo

git clone git@github.com: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/