Localized Pub Sub

mediator.js

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;
};

usage.js

// make mediator a mediator itself
mediator(mediator);

mediator.subscribe('foo', function (a, b) {
  console.log(a, b);
});

mediator.publish('foo', 1, 2);

// get a generic mediator with its own channels
var pubsub = mediator();
pubsub.subscribe;
pubsub.publish;

// or turn anything into a mediator
mediator(window);
publish;
subscribe;