/*!
* ee-first
* Copyright(c) 2014 Jonathan Ong
* MIT Licensed
*/
'use strict'
/**
* Module exports.
* @public
*/
module.exports = first
/**
* Get the first event in a set of event emitters and event pairs.
*
* @param {array} stuff
* @param {function} done
* @public
*/
function first(stuff, done) {
if (!Array.isArray(stuff))
throw new TypeError('arg must be an array of [ee, events...] arrays')
var cleanups = []
for (var i = 0; i < stuff.length; i++) {
var arr = stuff[i]
if (!Array.isArray(arr) || arr.length < 2)
throw new TypeError('each array member must be [ee, events...]')
var ee = arr[0]
for (var j = 1; j < arr.length; j++) {
var event = arr[j]
var fn = listener(event, callback)
// listen to the event
ee.on(event, fn)
// push this listener to the list of cleanups
cleanups.push({
ee: ee,
event: event,
fn: fn,
})
}
}
function callback() {
cleanup()
done.apply(null, arguments)
}
function cleanup() {
var x
for (var i = 0; i < cleanups.length; i++) {
x = cleanups[i]
x.ee.removeListener(x.event, x.fn)
}
}
function thunk(fn) {
done = fn
}
thunk.cancel = cleanup
return thunk
}
/**
* Create the event listener.
* @private
*/
function listener(event, done) {
return function onevent(arg1) {
var args = new Array(arguments.length)
var ee = this
var err = event === 'error'
? arg1
: null
// copy args to prevent arguments escaping scope
for (var i = 0; i < args.length; i++) {
args[i] = arguments[i]
}
done(err, ee, event, args)
}
}