sample-promise.js

var sleep = require('sleep');
var Promise = require('promise');

function random (low, high) {
    return Math.random() * (high - low) + low;
}

var task1 = new Promise(function (resolve, reject) {
	var until = 900;//random(900,1000);
	setTimeout(function(){
	    for(var i=0;i<10;i++)
	  	console.log('query1');
	  	resolve('query1');
	},until);
});

var task2 = new Promise(function (resolve, reject) {
	var until = 900;//random(900,1000);
	setTimeout(function(){
	    for(var i=0;i<10;i++)
	  	console.log('query2');
	  	resolve('query2');
	},until);
});

var task3 = new Promise(function (resolve, reject) {
	var until = 900;//random(900,1000);
	setTimeout(function(){
	    for(var i=0;i<10;i++)
	  	console.log('query3');
	  	resolve('query3');
	},until);
});

Promise.all([task1,task2,task3]).then(function(queries){console.log('process all queries to output view');}).then(function(results){console.log('finish');});

setTimeout(function(){console.log('Ended with setTimeout');},1);
sleep.sleep(1);

for(var i=0;i<1000000000;i++);

console.log('EOF');

//promises async queries, reduce bottleneck

//console.log
//EOF
//Ended with setTimeout
//query2
//query2
//query2
//query2
//query2
//query2
//query2
//query2
//query2
//query2
//query3
//query3
//query3
//query3
//query3
//query3
//query3
//query3
//query3
//query3
//query1
//query1
//query1
//query1
//query1
//query1
//query1
//query1
//query1
//query1
//process all queries to output view
//finish

function random (low, high) {
    return Math.random() * (high - low) + low;
}

var task1 = new Promise(function (resolve, reject) {
    var until    = random(900,1000),
        taskName = "task1";
    setTimeout(function(){
        var promises = [];
        for(var i=0;i<10;i++){
            var promise = new Promise(function(resolve2){
                var locI = JSON.stringify(i);
                setTimeout(function(){
                    console.log(taskName + " " + locI);
                    resolve2();
                },random(i,i*100));
            });
            promises.push(promise);
        }
        Promise.all(promises).then(function(){
            console.log(taskName + " done");
            resolve();
        });
    },until);
});

var task2 = new Promise(function (resolve, reject) {
    var until    = random(900,1000),
        taskName = "task2";
    setTimeout(function(){
        var promises = [];
        for(var i=0;i<10;i++){
            var promise = new Promise(function(resolve2){
                var locI = JSON.stringify(i);
                setTimeout(function(){
                    console.log(taskName + " " + locI);
                    resolve2();
                },random(i,i*100));
            });
            promises.push(promise);
        }
        Promise.all(promises).then(function(){
            console.log(taskName + " done");
            resolve();
        });
    },until);
});

var task3 = new Promise(function (resolve, reject) {
    var until    = random(900,1000),
        taskName = "task3";
    setTimeout(function(){
        var promises = [];
        for(var i=0;i<10;i++){
            var promise = new Promise(function(resolve2){
                var locI = JSON.stringify(i);
                setTimeout(function(){
                    console.log(taskName + " " + locI);
                    resolve2();
                },random(i,i*100));
            });
            promises.push(promise);
        }
        Promise.all(promises).then(function(){
            console.log(taskName + " done");
            resolve();
        });
    },until);
});

Promise.all([task1,task2,task3]).then(function(queries){console.log('process all queries to output view');}).then(function(results){console.log('finish');});

setTimeout(function(){console.log('Ended with setTimeout');},1);

for(var i=0;i<1000000000;i++);

console.log('EOF');

Itu i di for perlu di stringify karena dia mutable. Kalau gak di stringify hasilnya pasti 10.