jquery-ias-es6/src/callbacks.js

A jQuery plugin that turns your server-side pagination into an infinite scrolling one using AJAX

/**
 * IASCallbacks v2.3.1
 * https://infiniteajaxscroll.com
 *
 * This file is part of the Infinite AJAX Scroll package
 *
 * Copyright 2014-2018 Webcreate (Jeroen Fiege)
 */

var IASCallbacks = function (aJquery) {
  this.list = [];
  this.fireStack = [];
  this.isFiring = false;
  this.isDisabled = false;
  this.Deferred = aJquery.Deferred;

  /**
   * Calls all added callbacks
   *
   * @private
   * @param args
   */
  this.fire = function (args) {
    var context = args[0],
        deferred = args[1],
        callbackArguments = args[2];

    this.isFiring = true;

    for (var i = 0, l = this.list.length; i < l; i++) {
      if (this.list[i] != undefined) {
        if (false === this.list[i].fn.apply(context, callbackArguments)) {
          deferred.reject();

          break;
        }
      }
    }

    this.isFiring = false;

    deferred.resolve();

    if (this.fireStack.length) {
      this.fire(this.fireStack.shift());
    }
  };

  /**
   * Returns index of the callback in the list in a similar way as
   * the indexOf function.
   *
   * @param callback
   * @param {number} index index to start the search from
   * @returns {number}
   */
  this.inList = function (callback, index) {
    index = index || 0;

    for (var i = index, length = this.list.length; i < length; i++) {
      if (this.list[i].fn === callback || (callback.guid && this.list[i].fn.guid && callback.guid === this.list[i].fn.guid)) {
        return i;
      }
    }

    return -1;
  };

  return this;
};

IASCallbacks.prototype = {
  /**
   * Adds a callback
   *
   * @param callback
   * @returns {IASCallbacks}
   * @param priority
   */
  add: function (callback, priority) {
    var callbackObject = {fn: callback, priority: priority};

    priority = priority || 0;

    for (var i = 0, length = this.list.length; i < length; i++) {
      if (priority > this.list[i].priority) {
        this.list.splice(i, 0, callbackObject);

        return this;
      }
    }

    this.list.push(callbackObject);

    return this;
  },

  /**
   * Removes a callback
   *
   * @param callback
   * @returns {IASCallbacks}
   */
  remove: function (callback) {
    var index = 0;

    while (( index = this.inList(callback, index) ) > -1) {
      this.list.splice(index, 1);
    }

    return this;
  },

  /**
   * Checks if callback is added
   *
   * @param callback
   * @returns {*}
   */
  has: function (callback) {
    return (this.inList(callback) > -1);
  },


  /**
   * Calls callbacks with a context
   *
   * @param context
   * @param args
   * @returns {object|void}
   */
  fireWith: function (context, args) {
    var deferred = this.Deferred();

    if (this.isDisabled) {
      return deferred.reject();
    }

    args = args || [];
    args = [ context, deferred, args.slice ? args.slice() : args ];

    if (this.isFiring) {
      this.fireStack.push(args);
    } else {
      this.fire(args);
    }

    return deferred;
  },

  /**
   * Disable firing of new events
   */
  disable: function () {
    this.isDisabled = true;
  },

  /**
   * Enable firing of new events
   */
  enable: function () {
    this.isDisabled = false;
  }
};

export default IASCallbacks;