#350 Promise Chain Output

easy

javascript

promises

What will be the order of the following code:

Promise.resolve(1)
  .then(() => 2)
  .then(3)
  .then((value) => value * 3)
  .then(Promise.resolve(4))
  .then(console.log);

Promise.resolve(1)
  .then(() => 2)
  .then(3)
  .then((value) => value * 3)
  .then(Promise.resolve(4))
  .then(console.log);

Select one of the following:

The output will be: 6

Promise.resolve(1) → Initial value is 1
.then(() => 2) → Returns 2
.then(3) → Ignored because 3 is not a function, passes previous value 2
.then((value) => value * 3) → 2 * 3 = 6
.then(Promise.resolve(4)) → Ignored because it's not a function, passes previous value 6
.then(console.log) → Prints 6

Key points:

If .then() receives a non-function (like 3 or Promise.resolve(4)), it ignores that handler and passes the previous value through
Only function handlers are executed in the chain