este-library-oldschool/este/events/infinitescrollhandler.js

Library for github.com/steida/este.git

// Generated by github.com/steida/coffee2closure 900.1.18
/**
  @fileoverview Class to detect scrollable content reaching scroll end. Then
  'load' event is dispatched.

  @see /demos/events/infinitescrollhandler.html
 */
var extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.superClass_ = parent.prototype; return child; },
  hasProp = {}.hasOwnProperty;
goog.provide('este.events.InfiniteScrollHandler');
goog.require('este.Base');

/**
  @param {Element} element
  @param {Function} load
  @constructor
  @extends {este.Base}
 */
este.events.InfiniteScrollHandler = function(element, load) {
  this.element = element;
  this.load = load;
  este.events.InfiniteScrollHandler.superClass_.constructor.call(this);
}
extend(este.events.InfiniteScrollHandler, superClass);

/**
  @enum {string}
 */
este.events.InfiniteScrollHandler.EventType = {
  LOAD: 'load'
};

/**
  Threshold in px.
  @type {number}
 */
este.events.InfiniteScrollHandler.prototype.threshold = 0;

/**
  @type {Element}
  @protected
 */
este.events.InfiniteScrollHandler.prototype.element = null;

/**
  @type {Function}
  @protected
 */
este.events.InfiniteScrollHandler.prototype.load = null;

/**
  @param {boolean} enable
 */
este.events.InfiniteScrollHandler.prototype.setEnabled = function(enable) {
  if (enable) {
    return this.on(this.element, 'scroll', this.onElementScroll);
  } else {
    return this.off(this.element, 'scroll', this.onElementScroll);
  }
};

/**
  @param {goog.events.BrowserEvent} e
  @protected
 */
este.events.InfiniteScrollHandler.prototype.onElementScroll = function(e) {
  var shouldScroll;
  shouldScroll = this.element.scrollTop + this.element.offsetHeight >= this.element.scrollHeight - this.threshold;
  if (!shouldScroll) {
    return;
  }
  this.setEnabled(false);
  return this.load((function(_this) {
    return function() {
      return _this.setEnabled(true);
    };
  })(this));
};