promised-for

✌🏻 Promised-for loop

Promises/A+ 1.1 compliant promised-for loop for Browser and Node.js.

Installation

npm install promised-for

API

promisedFor(initialValue, testCallback, iterationCallback)

returns Promise

Parameters

• initialValue
  • can be Number|Object
  • will be passed to testCallback
• testCallback(initialValue)
  • can be Function
  • gets initialValue
  • should return Boolean
• iterationCallback(initialValue)
  • can be Function
  • gets initialValue
  • should return a Promise with updated initialValue

Basic usage

const pf = require('promised-for')

pf(0, // loop initialization
  (i) => i < 5, // test condition, gets initial value
  (i) => { // action, return callback with updated initial value
    console.log(i)

    // return promise
    return new Promise((resolve, reject) => {
      // Some async work
      setTimeout(() => resolve(i + 1), 500)
    })
  }).then((i) => {
    console.log('Done!')
  }).catch((e) => console.error(e)) // handle rejection

Output

0
1
2
3
4
Done!

Advance usage

const pf = require('promised-for')

pf({
  i: 0,
  j: 100,
  sum: 0
},
  (obj) => obj.i < 100,
  (obj) => {
    const { i, j, sum } = obj

    return new Promise((resolve, reject) => {
      setTimeout(() => resolve({
        i: i + 1,
        j: j - 1,
        sum: sum + i + j
      }), 500)
    })
  }).then((obj) => {
    console.log(obj.sum)
  }).catch((e) => console.error(e)) // handle rejection

Output

10000

Test

npm test

standard only for now. More to come.

Promises/A+ 1.1 compliant

License

MIT