resolve promise outside of promise

readme.md

IMAP connections are like this:

• send a message prefixed with a session-unique number
• on data, the string will have a prefix that is the number of the thing it's responding to
• there is no guarantee the responses will be in any order

callback.js

// the basic idea
function connect() {
	const map = {}
	const connection = makeConnection()
	connection.on('data', data => {
		const id = parseId(data)
		map[id].resolve(data)
	})
	connection.on('end', () => {
		Object.keys(map).forEach(id => map[id].reject('end'))
	})
	return function write(message) {
		const id = generateUniqueId()
		return new Promise((resolve, reject) => {
			map[id] = { resolve, reject }
		})
	}
}
// using it
const messenger = connect()
messenger('some command')
  .then(data => dataHandlerFunction)
  .catch(error => errorHandlerFunction)

event-emitter.js

// the basic idea
function connect() {
  const emitter = new EventEmitter()
  const connection = makeConnection()
	connection.on('data', data => {
		const id = parseId(data)
		emitter.emit(id, data)
	})
  return function write(message) {
    const id = generateUniqueId()
    return new Promise((resolve, reject) => {
      emitter.on(id, data => resolve(data))
    })
  }
}
// using it
const messenger = connect()
messenger('some command')
  .then(data => dataHandlerFunction)
  .catch(error => errorHandlerFunction)

Hi Tobias,

I'm trying to implement a similar logic and ended up finding your gist, but couldn't make it work. Were you able to resolve a promise from outside the promise? Would you have an example?

Thanks,

Roger