aboutsummaryrefslogtreecommitdiffstats
path: root/app/scripts/lib/nodeify.js
blob: 25be6537b473da2c07d60b53b7fba196e0c2851b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
const promiseToCallback = require('promise-to-callback')
const noop = function () {}

/**
 * A generator that returns a function which, when passed a promise, can treat that promise as a node style callback.
 * The prime advantage being that callbacks are better for error handling.
 *
 * @param {Function} fn The function to handle as a callback
 * @param {Object} context The context in which the fn is to be called, most often a this reference
 *
 */
module.exports = function nodeify (fn, context) {
  return function () {
    const args = [].slice.call(arguments)
    const lastArg = args[args.length - 1]
    const lastArgIsCallback = typeof lastArg === 'function'
    let callback
    if (lastArgIsCallback) {
      callback = lastArg
      args.pop()
    } else {
      callback = noop
    }
    promiseToCallback(fn.apply(context, args))(callback)
  }
}