Example of using reduce with promises and closure to create async results in series

async_series.js

// async_series.js
// example of using reduce with promises and closure to create async results in series

var q = require('Q');
var results = [1, 2, 3, 4, 5];

function workCollection(arr) {

    return arr.reduce(function(promise, item, index) {

        return promise.then(function(result) {

			return (function(i, r, idx){
				setTimeout(function(){
					console.log('item', i, 'result', r, 'index', idx);
				}, 1000 * idx);
                return true
			})(item, result, index);

		});

    }, q().then(function(){return true}));

}

	q()
		.then(function(){
			//console.log('then one test');
		})
		.then(function(){
			//console.log('then 2 test');
			workCollection(results);
		})
		.catch(function(err){
			console.log(err);
		});