How to write a function that returns a Promise resolving after one second?

A function that returns a Promise which resolves after one second can be written using setTimeout inside the Promise constructor:

function delayOneSecond() {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve();
    }, 1000);
  });
}

// Usage:
delayOneSecond().then(() => {
  console.log('One second has passed');
});