what do promises return js code example

Example 1: js return a promise

function myAsyncFunction(url) {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    xhr.open("GET", url);
    xhr.onload = () => resolve(xhr.responseText);
    xhr.onerror = () => reject(xhr.statusText);
    xhr.send();
  });
}

Example 2: promise javascript

const promiseA = new Promise( (resolutionFunc,rejectionFunc) => {
    resolutionFunc(777);
});
// At this point, "promiseA" is already settled.
promiseA.then( (val) => console.log("asynchronous logging has val:",val) );
console.log("immediate logging");

// produces output in this order:
// immediate logging
// asynchronous logging has val: 777