Module Pattern in JavaScript

module-pattern.js

// Module Pattern in JS

var FriendsModule = (function(){
  // private vars and functions

  var friends = ['Adam', 'Brittany', 'Russell', 'Erik', 'Hank'];

  var addFriend = function(friend) {
    friends.push(friend);
  };

  var listFriends = function() {
    var list = [];
    friends.forEach(function(friend, idx) {
      list.push(idx + 1 + ') ' + friend);
    });
    return list.join('\r\n');
  };

  var removeFriend = function(name) {
    friends.forEach(function(friend, idx) {
      if (name == friend)
        friends.splice(idx, 1);
    });
  };

  // public vars and aliases to private functions
  return {
    add: function(friend) {
      addFriend(friend);
    },

    count: function() {
      console.log(friends.length);
    },

    list: function() {
      console.log(listFriends());
    },

    remove: function(name) {
      removeFriend(name);
    }
  };

})();