React Waypoint

A React component to execute a function whenever you scroll to an element. Works in all containers that can scroll, including the window.

React Waypoint can be used to build features like lazy loading content, infinite scroll, or docking elements to the viewport on scroll.

Inspired by Waypoints, except this little library grooves the React way.

Demo

View demo page

Installation

npm

npm install react-waypoint --save

Bower

bower install react-waypoint --save

Usage

var Waypoint = require('react-waypoint');

<Waypoint
  onEnter={this._handleWaypointEnter}
  onLeave={this._handleWaypointLeave}
  threshold={0.2}
/>

Example: JSFiddle Example

Prop types

  propTypes: {

    /**
     * Function called when waypoint enters viewport
     * Both parameters will be null if the waypoint is in the
     * viewport on initial mount.
     *
     * @param {Event|null} event
     * @param {Waypoint.above|Waypoint.below|null} from
     */
    onEnter: PropTypes.func,

    /**
     * Function called when waypoint leaves viewport
     *
     * @param {Event|null} event
     * @param {Waypoint.above|Waypoint.below} to
     */
    onLeave: PropTypes.func,

    /**
     * Threshold - a percentage of the height of the visible
     * part of the scrollable parent (e.g. 0.1)
     */
    threshold: PropTypes.number
  },

Limitations

In this component we make a few assumptions that we believe are generally safe, but in some situations might present limitations.

• We determine the scrollable-ness of a node by inspecting its computed overflow-y or overflow property and nothing else. This could mean that a container with this style but that does not actually currently scroll will be considered when performing visibility calculations.
• We assume that waypoint is rendered within at most one scrollable container. If you render a waypoint in multiple nested scrollable containers, the visibility calculations will likely not be accurate.
• We also base the visibility calculations on the scroll position of the scrollable container (or window if no scrollable container is found). This means that if your scrollable container has a height that is greater than the window, it might trigger onEnter unexpectedly.

Credits

Credit to trotzig and lencioni for writing this component, and the Brigade team for open sourcing it.

Thanks to the creator of the original Waypoints library, imakewebthings.

License

MIT