____    _    _     _       __  __ _____    ___  _  _____ 
 / ___|  / \  | |   | |     |  \/  | ____|  / _ \| |/ |__ \
| |     / _ \ | |   | |     | |\/| |  _|   | | | | ' /  / /
| |___ / ___ \| |___| |___  | |  | | |___  | |_| | . \ |_| 
 \____/_/   \_|_____|_____| |_|  |_|_____|  \___/|_|\_\(_) 

This snippet of code gives you an easy way to support all Big Three flow control styles:

• Callbacks with (err, data) convention
• Promises
• Await/async (this is what you've always wanted, just learn it)

It also gives you to() function to nicely catch errors from promises without using two gazillion try/catch blocks.

Here's your base function:

import promcall from 'promised-callback'

async function Foo(bar, callback) {
  return await new Promise(async (resolve, reject) => {

    // When you call `done(data)` or `error(err)`, promises will be kept
    // and callbacks called. `await to(asyncFunc)` automatically catches errors from
    // asyncFunc's promises.

    const { done, error, to } = promcall(resolve, reject, callback)
    [err, result] = await to(doTheThing())
    err ? error(err) : done(result)
  })
}

This little helper is meant to be forked by you if you want to add your own custom handling for errors etc.