Async/Await Calculator example using `asyncawait` module

asyncawait_calculator.js

/**
 * Async/Await Calculator example
 *
 * Tested on Node v6
 */

const _async = require('asyncawait/async')
const _await = require('asyncawait/await')

const DELAY = 1000

const calculator = () => {
  const calc = (x) =>
    new Promise((resolve, reject) => {
      try {
        setTimeout(() => resolve(x), DELAY)
      } catch (err) {
        reject(err)
      }
    })

  const add = (a, b) => calc(a + b)
  const subtract = (a, b) => calc(a - b)
  const multiply = (a, b) => calc(a * b)
  const divide = (a, b) => calc(a / b)

  return {
    add,
    subtract,
    multiply,
    divide
  }
}

const add = _async((numbers, b) => {
  return numbers.map((a) => {
    console.log(`add: ${a} + ${b}`)
    const x = _await(calculator().add(a, b))
    console.log(`add result: ${x}`)
    console.log()
    return x
  })
})

const multiply = _async((numbers, b) => {
  return numbers.map((a) => {
    console.log(`multiply: ${a} x ${b}`)
    const x = _await(calculator().multiply(a, b))
    console.log(`multiply result: ${x}`)
    console.log()
    return x
  })
})

console.log('----- ADD -----')

add([ 5, 10, 15, 20, 25 ], 2).then((result) => {
  console.log('----- ADD RESULTS -----')
  console.log(result)
  console.log('----- END ADD -----')
  console.log()
})

console.log('----- MULTIPLY -----')

multiply([ 5, 10, 15, 20, 25 ], 2).then((result) => {
  console.log('----- MULTIPLY RESULTS -----')
  console.log(result)
  console.log('----- END MULTIPLY -----')
})