Promise short circuit behavior

promise_short_circuit.js

const fn1 = (a, b, x) => new Promise((resolve, reject) => {
  if (x) resolve('resolve x');
  console.log('after x');
  if (a) reject('reject a');
  console.log('after a');
  if (b) reject('reject b');
  console.log('after b');
  resolve('resolve c');
});
const fn2 = (a, b, x) => new Promise((resolve, reject) => {
  if (x) return resolve('resolve x');
  console.log('after x');
  if (a) return reject('reject a');
  console.log('after a');
  if (b) return reject('reject b');
  console.log('after b');
  resolve('resolve c');
});

console.log('<< fn1 >>');
fn1(1, 1, 1)
  .then(ret => console.log(ret))
  .catch(err => console.log(err));

console.log('<< fn2 >>');
fn2(1, 1, 1)
  .then(ret => console.log(ret))
  .catch(err => console.log(err));

console.log('hello world');

<< fn1 >>
after x
after a
after b
<< fn2 >>
hello world
resolve x
resolve x