How to work with Async

Async.js

// http://csbin.io/async
/*
-Async functions calls methods in browser.
-They reutrn a promise.
-Once promise is resolved or rejected the methods related to .then are called.
-This methods are put in the micro-queue which the event loop check after the global space is cleared and before checking 
the callback queue.
      |---> Global Space (stack
      |
      |
Event |--->   micro - queue
Loop  |
      |
      |--->   callback queue.
*/


/* CHALLENGE 1 */

function sayHowdy() {
  console.log('Howdy');
}

function testMe() {
  setTimeout(sayHowdy, 0);
  console.log('Partnah');
}
// After thinking it through, uncomment the following line to check your guess!
testMe(); // what order should these log out? Howdy or Partnah first?


/* CHALLENGE 2 */

function delayedGreet() {
  setTimeout(() => console.log('welcome'),3000);
}
// Uncomment the following line to check your work!
delayedGreet(); // should log (after 3 seconds): welcome

/* CHALLENGE 3 */

function helloGoodbye() {
  // ADD CODE HERE
  console.log('hello');
  setTimeout(() => console.log('good bye'),3000);
}
// Uncomment the following line to check your work!
// helloGoodbye(); // should log: hello // should also log (after 3 seconds): good bye


/* CHALLENGE 4 */

function brokenRecord() {
  // ADD CODE HERE
}
// Uncomment the following line to check your work!
// brokenRecord(); // should log (every second): hi again


/* CHALLENGE 5 */

function limitedRepeat() {
  // ADD CODE HERE
  var test = () => {
    console.log('hi for now');
  }
  var index = 0;
  var interval = setInterval(() => {
	index+=1;
  if (index > 5){
    clearInterval(interval);
  }
  else{
  	test()    
  }
    
},1000)

}
// Uncomment the following line to check your work!
// limitedRepeat(); // should log (every second, for 5 seconds): hi for now


/* CHALLENGE 6 */

function everyXsecsForYsecs(func,x,y) {
  // ADD CODE HERE
  var totalTime = 1;
  var interval = setInterval(()=>{
    if(x*totalTime <= y){
      totalTime++;
      func();
    }
    else{
      clearInterval(interval);
    }
  },x)
}
// Uncomment the following lines to check your work!
function theEnd() {
  console.log('This is the end!');
}
function sayHi(){
  console.log('hi.');
}
// everyXsecsForYsecs(theEnd, 2, 20); // should invoke theEnd function every 2 seconds, for 20 seconds): This is the end!
// everyXsecsForYsecs(sayHi, 1000,5000); 

/* CHALLENGE 7 */

function delayCounter(target, wait) {
	let index = 1
  return function(){
		var interval = setInterval(() => {
      if (index > target){
        clearInterval(interval);
      }
      console.log(index);
      index+=1
    },wait)    
  }
}

// UNCOMMENT THESE TO TEST YOUR WORK!
// const countLogger = delayCounter(10, 1000)
// countLogger();
// After 1 second, log 1
// After 2 seconds, log 2
// After 3 seconds, log 3

/* CHALLENGE 8 */

function promised (val) {
  // ADD CODE HERE
  return new Promise(function(resolve, reject) {
  // do a thing, possibly async, then…
	setTimeout(() => {
    resolve(val);
  },2000);
})

}

// UNCOMMENT THESE TO TEST YOUR WORK!
// const createPromise = promised('wait for it...');
// createPromise.then((val) => console.log(val)); 
// will log "wait for it..." to the console after 2 seconds

/* CHALLENGE 9 */

class SecondClock {
  constructor(cb) {
    // ADD CODE HERE
    this.cb = cb;
    this.initial = 0;
  }
  
  start(){
    this.interval = setInterval(()=>{
      this.initial+=1;
      this.cb(this.initial%11);
    },1000);
  }
  
  reset(){
    this.initial = 0;
    clearInterval(this.interval);
  }
  
  // ADD METHODS HERE
}

// UNCOMMENT THESE TO TEST YOUR WORK!
// const clock = new SecondClock((val) => { console.log(val) });
// console.log("Started Clock.");
// clock.start();
// setTimeout(() => {
//     clock.reset();
//     console.log("Stopped Clock after 6 seconds.");
// }, 61000);

/* CHALLENGE 10 */

function debounce(callback, interval) {
  // ADD CODE HERE
  let isFree = true;
  let intervalTimer;
  return function(){
    if(isFree){
      isFree = false;
      return callback();
    }
    intervalTimer = setTimeout(() => isFree=true,interval)
  }
}

// UNCOMMENT THESE TO TEST YOUR WORK!
function giveHi() { return 'hi'; }
const giveHiSometimes = debounce(giveHi, 3000);
console.log(giveHiSometimes()); // -> 'hi'
setTimeout(function() { console.log(giveHiSometimes()); }, 2000); // -> undefined
setTimeout(function() { console.log(giveHiSometimes()); }, 4000); // -> undefined
setTimeout(function() { console.log(giveHiSometimes()); }, 8000); // -> 'hi'
setTimeout(function() { console.log(giveHiSometimes()); }, 9000); // -> 'undefined'
setTimeout(function() { console.log(giveHiSometimes()); }, 12090); // -> 'hi'