Lightweight cross-browser library that enables you to create a watcher for a given element, and get back a callback when it has entered the viewport

Viewability Helper uses Intersection Observer API if available. If it's not, the library makes the calculations itself. Browser support for the Intersection Observer API can be found here.

Note: Not working when Intersection Observer is not supported and the script is running inside an iframe.

npm install --save viewability-helper

// import the module
import ViewabilityHelper from 'viewability-helper';
// -or-
const ViewabilityHelper = require('viewability-helper');

// Create a new observer for an element with a callback function
const myObserver = new ViewabilityHelper(element, callback);
// Fire in the hole!
myObserver.observe();

// With options
myObserver = new ViewabilityHelper(element, callback, {callbackParams: ['Element number 1']});

callbackParams (Array) - List of parameters passed to the callback function

intersectPercentage (String) - Intersection percentage, ex: "0", "0.2" etc..

scrollDimmer (Integer) - Interval for triggering element viewability watch (msec)

unobserve (Boolean) - Should the observer keep observing the element after first viewability event or not

rootMargin (String) - For Intersection Observer API, The root element margin

threshold (Array) - For Intersection Observer API, List of intersection ratio thresholds of the element with the viewport

Please first fork this repository, make your changes and then create a pull request.

Start by

npm install

And then build it with

npm run dev