1/*
2	A Promise is a proxy for a value not necessarily known when the promise is created. 
3    It allows you to associate handlers with an asynchronous action's eventual success 
4    value or failure reason.
5*/            
6let promise = new Promise((resolve , reject) => {
7  fetch("https://myAPI")
8    .then((res) => {
9      // successfully got data
10      resolve(res);
11    })
12    .catch((err) => {
13      // an error occured
14      reject(err);
15    });          
16});

1const myPromise = new Promise((resolve, reject) => {
2  setTimeout(() => {
3    resolve('foo');
4  }, 300);
5});
6
7myPromise
8  .then(handleResolvedA, handleRejectedA)
9  .then(handleResolvedB, handleRejectedB)
10  .then(handleResolvedC, handleRejectedC);
11

1new Promise((resolve, reject) => {
2  if (ok) { resolve(result) }
3  else { reject(error) }
4})
5 
6

1myPromise
2.then(handleResolvedA)
3.then(handleResolvedB)
4.then(handleResolvedC)
5.catch(handleRejectedAny)
6.finally(handleComplition)
7