createSubscriber.js

function createSubscriber() {
  'use strict';
  
  var subscriber = {};
  var f = {};

  if (typeof f !== 'object') {
    throw 'The argument for \'createSubscriber\' must be type object';
  }

  f.on = function (name, fn) {
    var i, n, x;
    var names = name.split(',');

    for (i = 0, n = names.length; i < n; i++) {
      x = names[i].trim();
      if (typeof subscriber[x] === 'undefined') {
        subscriber[x] = [];
      }
      if (subscriber[x].indexOf(fn) === -1) {
        subscriber[x].push(fn);
      }
    }
  };

  f.off = function (name, fn) {
    var index, n, i, x;
    var names = name.split(',');

    for (i = 0, n = names.length; i < n; i++) {
      x = names[i].trim();
      if (typeof subscriber[x] === 'undefined') {
        throw 'There are no subscribers for \'' + x + '\'';
      }
      index = subscriber[x].indexOf(fn);
      if (index !== -1) {
        subscriber[x].slice(index, 1);
      }
    }
  };

  f.trigger = function (name, e) {
    var index, n, i, x, j, k;
    var names = name.split(',');

    for (i = 0, n = names.length; i < n; i++) {
      x = names[i].trim();
      if (typeof subscriber[x] === 'object') {
        for (j = 0, k = subscriber[x].length; j < k; j++) {
          subscriber[x][j](e);
        }
      }
    }
  };
  return f;
}