var mediator = function (obj) {
  var channels = {};

  if (!obj) obj = {};

  obj.subscribe = function (channel, subscription) {
    if (!channels[channel]) channels[channel] = [];
    channels[channel].push(subscription);
  };

  obj.publish = function (channel) {
    if (!channels[channel]) return;
    var args = [].slice.call(arguments, 1);
    for (var i = 0, l = channels[channel].length; i < l; i++) {
      channels[channel][i].apply(this, args);
    }
  };

  return obj;
};