priteshjha4u

function promiseAll() {
  if (!arguments.length) {
    return Promise.resolve(null);
  }
  var args = arguments;
  if (args.length === 1 && Array.isArray(args[0])) {
    args = args[0];
  }
  var count = 1;
  var total = args.length;

priteshjha4u

@kangax's ES6 quiz, explained

@kangax created a new interesting quiz, this time devoted to ES6 (aka ES2015). I found this quiz very interesting and quite hard (made myself 3 mistakes on first pass).

Here we go with the explanations:

Question 1:

(function(x, f = () => x) {

priteshjha4u

//run this example function in chrome console to see async await in action
async function asyncAwaitExample() {

  let tmp = 1;
  let value1 = await getValueFromApi(2000); 
  let value2 = await getValueFromApi(4000); 
  //this function is here just to simulate a server/api behavior
  //returns a random value after provided time(in ms)
  function getValueFromApi(t) {
    return new Promise((rs, rj) => { setTimeout(v => { console.log(`getvalue call ${tmp} ---- ${v}`); tmp++; rs(v + v) }, t, Math.random().toString(36).substring(7)) }).then(v => v + v);