async example.js

// Declare the async function
async function addInFourSeconds(x) {
    // In 2 seconds, this Promise will be resolved with the value 10
    // Nothing else will be executed until these 2 seconds are over
    var y = await resolveAfterTwoSeconds(10);
    // print 10, since the above Promise has been resolved
    console.log(y);
    // In 2 seconds, this Promise will be resolved with the value 10 
    // Nothing else will be executed until these 2 seconds are over
    var z = await resolveAfterTwoSeconds(20);
    // print 20, since the above Promise has been resolved
    console.log(z);

    // At this point, y=10, z=10, and both are ready to be used     
    using .then()
    return x + y + z;
    // Run the above function using 5 as argument
    addInFourSeconds(5).then(value => {
        // this is the above “x+y+z”, equal to 5+10+20 = 35
        console.log(value); 
    });
}