Nodejs Array First or Default firstOrDefault(predicate)

Method Source Code

Array.prototype.firstOrDefault = function (predicate) {
    if (predicate && typeof predicate === 'function') {

        for (var i = 0; i < this.length; i++) {
            if (predicate(this[i])) return this[i];
        }/*  w ww.j  a  v a 2  s  . co m*/

        return null;
    } else {
        return this.length > 0 ? this[0] : null;
    }
};

Related

1. firstOrDefault(expr)

   "use strict";
   var firstOrDefault = function (array, expr) {
       if (typeof expr === "function") {
           array = array.filter(expr);
       return typeof array[0] === "undefined" ? null : array[0];
   };
   Array.prototype.firstOrDefault = function (expr) {
       return firstOrDefault(this, expr);
   ...
   

2. firstOrDefault(func)

   Array.prototype.firstOrDefault = function(func) {
     var elements = this.filter(func)
     if (elements.length > 0)
       return elements[0]
     else
       return undefined