joshwnj
React Visibility Sensor
Sensor component for React that notifies you when it goes in or out of the window viewport.
Sponsored by X-Team
Install
npm install react-visibility-sensor
Including the script directly
Useful if you want to use with bower, or in a plain old <script> tag.
In this case, make sure that React and ReactDOM are already loaded and globally accessible.
- Plain: https://unpkg.com/react-visibility-sensor@5.0.1/dist/visibility-sensor.js
- Minified https://unpkg.com/react-visibility-sensor@5.0.1/dist/visibility-sensor.min.js
Take a look at the umd example to see this in action
Example
View an example on codesandbox
Or if you'd like to try building an example yourself locally, here's another:
To run the example locally:
npm run build-example- open
example/index.htmlin a browser
General usage goes something like:
const VisibilitySensor = require('react-visibility-sensor');
function onChange (isVisible) {
console.log('Element is now %s', isVisible ? 'visible' : 'hidden');
}
function MyComponent (props) {
return (
<VisibilitySensor onChange={onChange}>
<div>...content goes here...</div>
</VisibilitySensor>
);
}You can also pass a child function, which can be convenient if you don't need to store the visibility anywhere:
function MyComponent (props) {
return (
<VisibilitySensor>
{({isVisible}) =>
<div>I am {isVisible ? 'visible' : 'invisible'}</div>
}
</VisibilitySensor>
);
}Props
onChange: callback for whenever the element changes from being within the window viewport or not. Function is called with 1 argument(isVisible: boolean)active: (defaulttrue) boolean flag for enabling / disabling the sensor. Whenactive !== truethe sensor will not fire theonChangecallback.partialVisibility: (defaultfalse) consider element visible if only part of it is visible. Also possible values are - 'top', 'right', 'bottom', 'left' - in case it's needed to detect when one of these become visible explicitly.offset: (default{}) with offset you can define amount of px from one side when the visibility should already change. So in example settingoffset={{top:10}}means that the visibility changes hidden when there is less than 10px to top of the viewport. Offset works along withpartialVisibilityminTopValue: (default0) consider element visible if only part of it is visible and a minimum amount of pixels could be set, so if at least 100px are in viewport, we mark element as visible.intervalCheck: (defaulttrue) when this is true, it gives you the possibility to check if the element is in view even if it wasn't because of a user scrollintervalDelay: (default100) integer, number of milliseconds between checking the element's position in relation the the window viewport. Making this number too low will have a negative impact on performance.scrollCheck: (default:false) by making this true, the scroll listener is enabled.scrollDelay: (default:250) is the debounce rate at which the check is triggered. Ex: 250ms after the user stopped scrolling.scrollThrottle: (default:-1) by specifying a value > -1, you are enabling throttle instead of the delay to trigger checks on scroll event. Throttle supercedes delay.resizeCheck: (default:false) by making this true, the resize listener is enabled. Resize listener only listens to the window.resizeDelay: (default:250) is the debounce rate at which the check is triggered. Ex: 250ms after the user stopped resizing.resizeThrottle: (default:-1) by specifying a value > -1, you are enabling throttle instead of the delay to trigger checks on resize event. Throttle supercedes delay.containment: (optional) element to use as a viewport when checking visibility. Default behaviour is to use the browser window as viewport.delayedCall: (defaultfalse) if is set to true, wont execute on page load ( prevents react apps triggering elements as visible before styles are loaded )children: can be a React element or a function. If you provide a function, it will be called with 1 argument{isVisible: ?boolean, visibilityRect: Object}
It's possible to use both intervalCheck and scrollCheck together. This means you can detect most visibility changes quickly with scrollCheck, and an intervalCheck with a higher intervalDelay will act as a fallback for other visibility events, such as resize of a container.
Thanks
Special thanks to contributors
License
MIT