Promise Workshop

There are two ways to return a promise from a function.

1. Using the constructor:

const isGreaterThanTen = number => {
  return new Promise( (resolve, reject) => {
    return number > 10
      ? resolve(number)
      : reject(Error('this number is TOO SMALL'));
  });
}

isGreaterThanTen(12)
.then( /* will be called */ )
.catch( /* not called */ )

2. Using the resolve/reject methods:

const isGreaterThanTen = number => {
  return number > 10
    ? Promise.resolve(number)
    : Promise.reject(Error('this number is TOO SMALL'));
}

isGreaterThanTen(5)
.then( /* not called */ )
.catch( /* will be called */ )

Try to use the methods when possible, but if you are using a callback inside the function (such as with XMLHttpRequest), you will have to use the constructor.

1. Open index.html in your browser.
2. Finish the methods in functions.js to pass the tests in tests.js!

Promise Docs