1
 2/**
 3 * Module exports.
 4 */
 5
 6module.exports = on;
 7
 8/**
 9 * Helper for subscriptions.
10 *
11 * @param {Object|EventEmitter} obj with `Emitter` mixin or `EventEmitter`
12 * @param {String} event name
13 * @param {Function} callback
14 * @api public
15 */
16
17function on (obj, ev, fn) {
18  obj.on(ev, fn);
19  return {
20    destroy: function () {
21      obj.removeListener(ev, fn);
22    }
23  };
24}