promise_generic.js

function getMoneyBack(money) {
  money = String(money)  // force the rejectkk
  return new Promise((resolve, reject) => {
    if (typeof money !== 'number') {
      reject(new Error('money is not a number'))
    } else {
      resolve(money)
    }
  })
}

getMoneyBack(1200).then((money) => {
  console.log(money)
})
  .catch(error => {
    console.error(error)
  })