Here you can find the source of first(num)
Array.prototype.first = function (num) { if (num !== undefined) { return this.slice(0, num); }//from w ww . ja v a2 s . c o m return this[0]; };
Array.prototype.first = function(func) { var result = []; for(var i=0;i<this.length;i++) if (func(this[i])) return this[i]; return null;
Array.prototype.first = function (func) { var length = this.length, item = null; for (var i = 0; i < length; i++) { if (func(this[i])) { return this[i]; return item; ...
Array.prototype.first = function(matching) { for (var i = 0; i < this.length; i++) { var entry = this[i]; if (matching(entry) == true) return this[i]; return null;
Array.prototype.first = function (n) { 'use strict'; return this.slice(0, n || 1); };
Array.prototype.first = function(n) { if (this.length === 0 || n < 0) return void 0; if (n === undefined) return this[0]; if (n === 0) return []; return this.initial(this.length - n); };
Array.prototype.first = function(predicate) { for (var i = 0, l = this.length; i < l; i++) { if (predicate(this[i])) return this[i];
Array.prototype.first = function (predicate) { for (var i = 0; i < this.length; ++i) { if (predicate(this[i])) return this[i]; };
Array.prototype.first = function (predicate, def) { var l = this.length; if (!predicate) return l ? this[0] : def == null ? null : def; for (var i = 0; i < l; i++){ if (predicate(this[i], i, this)) return this[i]; return def == null ? null : def; }; ...