Dictionary of js

function Dictionary() { ???this.datastore = new Array();};Dictionary.prototype = { ???constructor: Dictionary, ???add: function(key, value) { ???????this.datastore[key] = value; ???}, ???find: function(key) { ???????return this.datastore[key]; ???}, ???remove: function(key) { ???????delete this.datastore[key]; ???}, ???showAll: function() { ???????var _this = this; ???????Object.keys(this.datastore).sort().forEach(function(val, key) { ???????????console.log(val + " -> " + _this.datastore[val]); ???????}); ???}, ???count: function() { ???????var n = 0; ???????Object.keys(this.datastore).forEach(function(val, key) { ???????????++n; ???????}); ???????return n; ???}, ???clear: function() { ???????var _this = this; ???????Object.keys(this.datastore).forEach(function(val, key) { ????????????delete _this.datastore[val]; ???????}); ???}};var telephoneBook = new Dictionary();telephoneBook.add(‘Tom‘, 13713750081);telephoneBook.add(‘Bom‘, 13713550081);telephoneBook.add(‘Cindy‘, 43713750081);telephoneBook.showAll();