react-sizeme

What is react-sizeme?

The react-sizeme package is a React higher-order component (HOC) that makes it easy to get the dimensions of a component. It provides a way to measure the size of a component and pass those dimensions as props to the component, enabling responsive design and dynamic rendering based on component size.

What are react-sizeme's main functionalities?

Basic Usage

This example demonstrates the basic usage of react-sizeme. The SizeMe HOC is used to wrap a component, and it injects the size (width and height) as props into the wrapped component.

```jsx
import React from 'react';
import { SizeMe } from 'react-sizeme';

const MyComponent = ({ size }) => (
  <div>
    {`Width: ${size.width}, Height: ${size.height}`}
  </div>
);

const SizeAwareComponent = SizeMe({ monitorHeight: true })(MyComponent);

export default SizeAwareComponent;
```

Using with Functional Components

This example shows how to use react-sizeme with functional components. The SizeMe HOC wraps the functional component and provides the size as props.

```jsx
import React from 'react';
import { SizeMe } from 'react-sizeme';

const MyFunctionalComponent = ({ size }) => (
  <div>
    {`Width: ${size.width}, Height: ${size.height}`}
  </div>
);

const SizeAwareFunctionalComponent = SizeMe({ monitorHeight: true })(MyFunctionalComponent);

export default SizeAwareFunctionalComponent;
```

Custom Configuration

This example demonstrates how to use custom configuration options with react-sizeme. The options include monitoring width and height, setting a refresh rate, and disabling the placeholder.

```jsx
import React from 'react';
import { SizeMe } from 'react-sizeme';

const MyComponent = ({ size }) => (
  <div>
    {`Width: ${size.width}, Height: ${size.height}`}
  </div>
);

const SizeAwareComponent = SizeMe({
  monitorWidth: true,
  monitorHeight: true,
  refreshRate: 100,
  noPlaceholder: true
})(MyComponent);

export default SizeAwareComponent;
```

Other packages similar to react-sizeme

react-measure

react-measure is a package that provides a higher-order component and a render prop component to measure the size of a component. It offers more flexibility with render props and supports more detailed measurements like margins and padding. Compared to react-sizeme, react-measure provides more granular control over what measurements are taken and how they are used.

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 component. It is simpler and more focused on detecting resize events rather than providing detailed size measurements. Compared to react-sizeme, react-resize-detector is more lightweight and easier to use for simple resize detection.

react-use-measure

react-use-measure is a hook-based package that provides a way to measure the size of a component using the ResizeObserver API. It is modern and hook-based, making it a good fit for functional components and hooks-based codebases. Compared to react-sizeme, react-use-measure is more modern and leverages the latest React features.

README

Make your React Components aware of their width and height

• Responsive Components!
• Easy to use.
• Extensive browser support.
• Supports any Component type, i.e. stateless/class.
• Works with React 0.14.x and 15.x.x.
• 7.67KB gzipped standalone, even smaller if bundled into your own project.

Release Notes

See here: https://github.com/ctrlplusb/react-sizeme/releases

What is this for?

Give your Components the ability to have render logic based on their height/width.

Live Demo

It really does work! Look:

https://react-sizeme-example-tupkctjbbt.now.sh

Simple Example

Below is a super simple example highlighting the use of the library. Read the Usage section in its entirety for a full description on configuration and usage.

import SizeMe from 'react-sizeme';

class MyComponent extends Component {
  render() {
    // We receive width and height via "size" prop!
    const { width } = this.props.size;
  
    return (
      <div>My width is {width}px</div>
    );
  }
}

// Wired up here!
export default SizeMe()(MyComponent);

Usage and API Details

First install the library.

npm install react-sizeme

Then identify a Component you would like to make aware of its size. We provide you with a helper function called SizeMe. You can import it like so:

import SizeMe from 'react-sizeme';

You first have to pass the SizeMe function a configuration object. The entire configuration object is optional, as is each of its properties, in which case the defaults would be used. Here is a full configuration example with the default values for each of the properties:

const SizeMeHOC = SizeMe({
  // If true, then any changes to your Components rendered width will cause an 
  // recalculation of the "size" prop which will then be be passed into 
  // your Component.
  // If false, then any changes to your Components rendered width will NOT 
  // cause any recalculation of the "size" prop. Additionally any "size" prop 
  // that is passed into your Component will always have a `null` value 
  // for the "width" property.
  monitorWidth: true, 
  // If true, then any changes to your Components rendered height will cause an 
  // recalculation of the "size" prop which will then be be passed into 
  // your Component.
  // If false, then any changes to your Components rendered height will NOT 
  // cause any recalculation of the "size" prop. Additionally any "size" prop 
  // that is passed into your Component will always have a `null` value 
  // for the "height" property.
  monitorHeight: false,
  // The maximum frequency, in milliseconds, at which size changes should be 
  // recalculated when changes in your Component's rendered size are being
  // detected. This should not be set to lower than 16.
  refreshRate: 16
});

IMPORTANT: We don't monitor height by default, so if you use the default settings and your component only changes in height it won't cause a recalculation of the size prop. I figured that in most cases we care about the width only and it would be annoying if vertical text spanning kept throwing out updates.

IMPORTANT: If you aren't monitoring a specific dimension (width or height) you will be provided null values for the respective dimension. This is to avoid any possible misconfigured implementation whoopsies.

IMPORTANT: refreshRate is set very low. If you are using this library in a manner where you expect loads of active changes to your components dimensions you may need to tweak this value to avoid browser spamming.

When you execute the SizeMe function it will return a Higher Order Component. You can use this Higher Order Component to decorate any of your existing Components with the size awareness ability. Each of the Components you decorate will then recieve a size prop, which is an object of schema { width: number, height: number } - the numbers representing pixel values. Below is an example:

class MyComponent extends Component {
  render() {
    const { width, height } = this.props.size;
  
    return (
      <div>My size is {width}px x {height}px</div>
    );
  }
}

export default SizeMeHOC(MyComponent);  // Wired up here!

That's it. Its really useful for doing things like optionally loading a child component based on the available space.

Here is an full example of that in action:

import React, { PropTypes } from 'react';
import LargeChildComponent from './LargeChildComponent';
import SmallChildComponent from './SmallChildComponent';
import SizeMe from 'react-sizeme';

function MyComponent(props) {
  const { width, height } = props.size; 

  const ToRenderChild = height > 600 
    ? LargeChildComponent
    : SmallChildComponent;

  return (
    <div>
      <h1>My size is {width}x{height}</div>
      <ToRenderChild />
    </div>
  );
}
MyComponent.propTypes = {
  size: PropTypes.shape({
    width: PropTypes.number.isRequired,
    height: PropTypes.number.isRequired,
  })
}

export default SizeMe({ monitorHeight: true })(MyComponent);

On the First Render of your Component

Ok, we have a bit of a chicken/egg scenario. We can't know the width/height of your Component until it is rendered. This can lead to less than ideal cases, for example based on the rendered size of your component you may have logic that renders the internals of your component entirely. This can lead to some wasteful rendering.

Therefore for the first render of your component we actually render a lightweight placeholder in order to obtain the width/height for your Component render. In addition to this, if you were passing any className or style props into your object these will be used for the render of the placeholder, which can be useful in cases where you are pre-rendering it with specific dimensions based on the CSS.

An example of this:

import cssStyles from './styles.css';
import MySizeAwareComponent from './MySizeAwareComponent';

const inlineStyle = {
  backgroundColor: 'pink'
};

function App() {
    return (
      <MySizeAwareComponent 
        className={cssStyles.foo} 
        style={inlineStyle} />
    );
}

In cases where the styles/classes are contained within your component and you want more accurate first-render size resolving we recommend that you create a wrapper component that passes the className/style into your component. For example we could refactor our MySizeAwareComponent like so:

import React from 'react';
import cssStyles from './styles.css';
import SizeMe from 'react-sizeme';

class MyComponent extends Component {
  render() {
    const className = this.props.className;
    const { width, height } = this.props.size;
  
    return (
      <div className={className}>
        My size is {width}px x {height}px
      </div>
    );
  }
}

const MySizeAwareComponent = SizeMeHOC(MyComponent);

// We create this wrapper component so that our size aware rendering
// will have a handle on the rendered components css classname.
function MyComponentWrapper(props) {
  return (
    <MySizeAwareComponent className={cssStyles.foo} {...props} />
  );
}

export default MyComponentWrapper;

Things to consider

The intention of this library to aid in initial render on a target device, i.e. mobile/tablet/desktop. In this case we just want to know the size as fast as possible. Therefore the refreshRate is configured with a very low value - specifically updates will occur within 16ms time windows.

If however you wish to use this library to wrap a component that you expect to be resized via user/system actions then I would recommend that you consider setting the refreshRate to a higher setting so that you don't spam the browser with updates.

Caveats.

• Server Side Rendering is not supported. I am still thinking of the best approach on what to do in the case of a SSR request. Perhaps I will just return null values for width/height. Undecided. Any recommendations are welcome.
• Whilst execution is performant and we try and do smart rendering mechanisms we don't recommend that you place a crazy amount of size aware components into your render tree. If you do require this I highly recommend you do some decent browser testing for impact.

Extreme Appreciation!

We make use of the awesome element-resize-detector library. This library makes use of an scroll/object based event strategy which outperforms window resize event listening dramatically. The original idea for this approach comes from another library, namely css-element-queries by Marc J. Schmidt. I recommend looking into these libraries for history, specifics, and more examples. I love them for the work they did, whithout which this library would not be possible. :sparkle-heart: