Promises.js

//Single Promise Object
new Promise((resolve, reject) => {
    // Your Code which you are unsure about execution time duration.
    resolve();//OR reject();
    
})
.then(() => {
//If resolve()
console.log('Do this');
})
.catch(() => {
		//If Reject
    console.log('Do that');
})
.then(() => {
    console.log('Do this whatever happened before');
});

//-------------------------------------------------------------------------------

let promise=new Promise((resolve, reject) => {
    // Your Code which you are unsure about execution time duration.
    resolve();//OR reject();
    
});

promise().then(() => {
    console.log('Resolved');
});