Nodejs Array First Predicate first(predicate, def)

Method Source Code

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];
   }//from  w  ww  . java  2 s  .  c  om

   return def == null ? null : def;
};

Related

1. first(n)

   Array.prototype.first = function (n) {
       'use strict';
       return this.slice(0, n || 1);
   };
   

2. first(n)

   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);
   };
   

3. first(num)

   Array.prototype.first = function (num) {
      if (num !== undefined) {
         return this.slice(0, num);
      return this[0];
   };
   

4. first(predicate)

   Array.prototype.first = function(predicate) {
       for (var i = 0, l = this.length; i < l; i++) {
           if (predicate(this[i]))
               return this[i];
   

5. first(predicate)

   Array.prototype.first = function (predicate) {
       for (var i = 0; i < this.length; ++i) {
           if (predicate(this[i]))
               return this[i];
   };