Async and Await

From https://www.w3schools.com/Js/js_async.asp

"async and await make promises easier to write"

async makes a function return a Promise

async function myFunction() {
  return "Hello";
}

...is the same as...

function myFunction() {
  return Promise.resolve("Hello");
}

await makes a function wait for a Promise

await can only be used inside an async function.

Example

The resolve and reject args to the new Promise() are pre-defined by JavaScript.

Often we will not need reject.

async function myDisplay() {
  let myPromise = new Promise(function(resolve, reject) {
    resolve("I love You !!");
  });
  document.getElementById("demo").innerHTML = await myPromise;
}

myDisplay();