Create Observable Array - Node.js Data Structure

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Description

Create Observable Array

Demo Code

var ObservableArray = (function() {
  'use strict';//from   w  w  w .  j  av a 2s .  co  m

  function ObservableArray() {
    this.length = 0;
    this.listeners = [];
  }

  ObservableArray.prototype.push = function() {
    var self = this;
    Array.prototype.forEach.call(arguments, function(element) {
      Array.prototype.push.call(self, element);
    });

    this.alert([].slice.call(arguments), 'add');
    return this;
  };

  ObservableArray.prototype.extend = function(array) {
    var self = this;
    Array.prototype.forEach.call(array, function(element) {
      Array.prototype.push.call(self, element);
    });
    this.alert(array, 'add');

    return this;
  };

  ObservableArray.prototype.indexOf = function(item) {
    return Array.prototype.indexOf.call(this, item);
  };

  ObservableArray.prototype.clear = function() {
    this.length = 0;
    this.alert([], 'remove');
  };

  ObservableArray.prototype.remove = function() {
    var self = this;
    Array.prototype.forEach.call(arguments, function(element) {
      var index = self.indexOf(element);
      if (index !== -1) {
        Array.prototype.splice.call(self, index, 1);
      }
    });

    this.alert([].slice.call(arguments), 'remove');
    return this;
  };

  ObservableArray.prototype.listen = function(listener) {
    this.listeners.push(listener);

    return this;
  };

  ObservableArray.prototype.unlisten = function(listener) {
    var index = this.listeners.indexOf(listener);
    if (index === -1) {
      throw 'Cannot remove unattached listener.';
    }
    this.listeners.splice(index, 1);

    return this;
  };

  ObservableArray.prototype.alert = function(values, type) {
    var self = this;
    this.listeners.forEach(function(listener) {
      listener(values, type, self);
    });

    return this;
  };

  return ObservableArray;
})();

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