promises.js

console.log('A');

const FetchKeys = new Promise((resolve, reject) => {
    setTimeout(function () {
        resolve('Hello world!');
    }, 1000);
});

Promise.all([FetchKeys])
    .then(res => {
        console.log('C: ', res);
    });

FetchKeys
    .then(res => {
        console.log('D:', res);
    });

console.log('E');