2nd Example of a JS Promise: A cleaner code in case you have many callbacks in your JS.

promiseDepenencies.js

//Promise Dependencies (after promiseExplanation)
//In this Example first you clean the room, then remove the garbage and finally win an icecream.
//Here also im directly resolving the promises, real life is code and check if resolved or reject.

let cleanRoom = function(){
	return new Promise(function(resolve, reject){
		resolve('I Cleaned the Room');
	});
};

let removeGarbage = function(message){
	return new Promise(function(resolve, reject){
		resolve(message + ' then I removed Garbage');
	});
};

let winIceCream = function(message){
	return new Promise(function(resolve, reject){
		resolve(message + ' So I won an Icecream!');
	});
};

//Executing dependant functions

cleanRoom().then(function(result){ //Executes cleaning the room and if its resolved...
//Remember that the result argument is to carry the resolve.
	return removeGarbage(result); //Executes remove the garbage and if its resolved...
}).then(function(result){
	return winIceCream(result); //Executes winning an Icecream!
}).then(function(result){ //If Icecream is resolved...
	console.log('Finished: ' + result); //log the price to console!
});

//Promise.all only excecutes after all promises inside has succesfully finished

Promise.all([cleanRoom(), removeGarbage(), winIceCream()]).then(function(){
	console.log('All finished');
});

//Promise.race excecutes if any of the promises inside has succesfully finished

Promise.race([cleanRoom(), removeGarbage(), winIceCream()]).then(function(){
	console.log('One has finished');
});

To see results: Check in JSFiddle and open the dev tools console.

Notice that when running, promises.all and promises.race executes before the dependencies (I think .all and .race is faster code)...