source: Dev/trunk/src/client/dojo/promise/first.js

define([
        "../_base/array",
        "../Deferred",
        "../when"
], function(array, Deferred, when){
        "use strict";

        // module:
        //              dojo/promise/first

        var forEach = array.forEach;

        return function first(objectOrArray){
                // summary:
                //              Takes multiple promises and returns a new promise that is fulfilled
                //              when the first of these promises is fulfilled.
                // description:
                //              Takes multiple promises and returns a new promise that is fulfilled
                //              when the first of these promises is fulfilled. Canceling the returned
                //              promise will *not* cancel any passed promises. The promise will be
                //              fulfilled with the value of the first fulfilled promise.
                // objectOrArray: Object|Array?
                //              The promises are taken from the array or object values. If no value
                //              is passed, the returned promise is resolved with an undefined value.
                // returns: dojo/promise/Promise

                var array;
                if(objectOrArray instanceof Array){
                        array = objectOrArray;
                }else if(objectOrArray && typeof objectOrArray === "object"){
                        array = [];
                        for(var key in objectOrArray){
                                if(Object.hasOwnProperty.call(objectOrArray, key)){
                                        array.push(objectOrArray[key]);
                                }
                        }
                }

                if(!array || !array.length){
                        return new Deferred().resolve();
                }

                var deferred = new Deferred();
                forEach(array, function(valueOrPromise){
                        when(valueOrPromise, deferred.resolve, deferred.reject);
                });
                return deferred.promise;        // dojo/promise/Promise
        };
});