Nodejs Array First Predicate first(f)

Method Source Code

Array.prototype.first = function(f){
    var i = 0;//from ww w  .  j  av  a  2s  . c  o  m

    while(i < this.length){
        if(f == undefined){
            return this[i];
        }
        if(f(this[i])){
           return this[i];
        }
        i++;
    }
    return null;
};

Related

1. first(fn)

   Array.prototype.first = function(fn) {
       if (Object.prototype.toString.call(this) !== '[object Array]') {
           throw new TypeError("`this` must be Array, not " + typeof this);
       if (typeof fn === 'undefined') {
           return this[0];
       if (typeof fn !== 'function') {
           throw new TypeError("Optional `argument[0]` must be predicate function if defined");
   ...
   

2. first(func)

   Array.prototype.first = function(func) {
     return this.where(func)[0];
   };
   

3. first(func)

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

4. first(func)

   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;
   ...