yield/generator/bluebird

yield_generator.js

// Idea 1: https://www.promisejs.org/generators/
// Idea 2: http://bluebirdjs.com/docs/api/promise.coroutine.html

const asyncDemo = Promise.coroutine(function* () {
  try {
    const res = yield getJSON()
    console.log(res.value)
  } catch (err) {
    console.log(err)
  }
})

function getJSON() {
  return new Promise((resolve, reject) => {
    const value = Math.ceil(Math.random() * 5000)

    setTimeout(() => {
      console.log('Random Value: ', value)

      if (value % 2 === 0) {
        resolve({ value })
      } else {
        reject(new Error('An error occurred with the following async request'))
      }
    }, 2000)
  });
}