94 lines
1.7 KiB
JavaScript
94 lines
1.7 KiB
JavaScript
/*!
|
|
* 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);
|
|
};
|
|
}
|