入れ子Promise

nestedPromise.js

const wait = true;
const success = false;

const promise2 = new Promise((res, rej) => {
  if (success) {
    setTimeout(res, 1000, 2)
  } else {
    rej(3)
  }
});

const promise1 = new Promise((res, rej) => {
  if (!wait)  {
    res(1)
  } else {
    promise2.then(v => res(v)).catch(e => res(e))
  }
});

promise1.then(v => console.log(v)).catch(e => console.log(e))