Here you can find the source of first()
// A JavaScript object is a table mapping string property names to values. // This makes objects pleasantly lightweight for implemeting dictionaries: // variable-sized collections mapping strings to values. var dict = { path: 24, montes:23, mike: 37, andrea: 21} var friends = []/*from w w w .ja va2 s . c om*/ for (var name in dict) { friends.push(name + ":" + dict[name]) } console.log(friends) // Deceptively, since we can add propertie to any type of JavaScript object // this usage pattern will sometimes appear to work: var dictAux = {} dictAux.alice = 34 dictAux.bob = 4 dictAu.chirs = 3 Array.prototype.first = function () { return this[0] } Array.prototype.last = function () { return this[this.length - 1] } var names = [] for (var name in dictAux) { names.push(name) } console.log(names)
Array.prototype.first = function() { return this[0]; Array.prototype.last = function() { return this.reverse()[0];
Array.prototype.first = function(){ if(this.length > 0) return this[0]; return null; };
Array.prototype.first = function() { if (this[0] !== undefined) return this[0] else { throw new TypeError("Can't get first element of an empty array.")
"use strict"; Array.prototype.first = function () { if (this.length === 0) { throw "Empty string doesn't have first element"; return this[0]; }; console.log(["a", "b", 3].first());
Array.prototype.first = function () { return this[0]; };
Array.prototype.first = function(){ if (this.length > 0) return this[0]; else return [];
Array.prototype.first = function () { this.current = 0; return jQuery.extend(true, [], this[this.current]); }; Array.prototype.last = function () { this.current = this.length - 1; return jQuery.extend(true, [], this[this.length - 1]); }; Array.prototype.next = function () { ...
Array.prototype.first = function () { return this[0]; };
Array.prototype.first = function() { return this[0]; Array.prototype.last = function() { return this[this.length-1];