javascript promise then 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: nodejs promise then example

p.then(onFulfilled, onRejected);

p.then(function(value) {
   //  run
  }, function(reason) {
  // fail
});