react-lite-misc/lib/module/wheeling.js

Misc Components of jianliao.com

(function() {
  var React, T, debounce, div;

  React = require('react');

  debounce = require('../util/debounce');

  div = React.createFactory('div');

  T = React.PropTypes;

  module.exports = React.createClass({
    displayName: 'wheeling',
    propTypes: {
      delay: T.number,
      onScroll: T.func.isRequired
    },
    getDefaultProps: function() {
      return {
        delay: 400
      };
    },
    componentDidMount: function() {
      this._rootEl = this.refs.root;
      this._wasGoingUp = false;
      this._wasGoingDown = false;
      return this.debounceDetect = debounce(this.detect, this.props.delay);
    },
    onWheel: function(event) {
      if (event.deltaY > 0) {
        this._wasGoingUp = false;
        this._wasGoingDown = true;
      } else if (event.deltaY < 0) {
        this._wasGoingUp = true;
        this._wasGoingDown = false;
      }
      return this.debounceDetect();
    },
    detect: function() {
      var info;
      info = {
        atTop: this._rootEl.scrollTop === 0,
        atBottom: (this._rootEl.scrollTop + this._rootEl.clientHeight) === this._rootEl.scrollHeight,
        goingUp: this._wasGoingUp,
        goingDown: this._wasGoingDown
      };
      return this.props.onScroll(info);
    },
    render: function() {
      return div({
        ref: 'root',
        className: 'wheeling',
        onWheel: this.onWheel
      }, this.props.children);
    }
  });

}).call(this);