promise-3.js

function printLater (number) {
  return new Promise( // return a new Promise
    (resolve, reject) => { // Take resolve and reject as parameters
      setTimeout(() => {
        if (number > 5) {
          // reject causes an error
          return reject('number is greater than 5')
        }
        resolve(number + 1) // return number + 1
        console.log(number)
      }, 1000)
    }
  )
}

printLater(1).
  then(num => printLater(num)).
  then(num => printLater(num)).
  then(num => printLater(num)).
  then(num => printLater(num)).
  then(num => printLater(num)).
  catch(e => console.log(e))