Strategies as functions

function_strategies.js

// Greeter is a class of object that can greet people.
// It can learn different ways of greeting people through
// 'Strategies.'
//
// This is the Greeter constructor.
var Greeter = function(strategy) {
  this.strategy = strategy;  
};

// Greeter provides a greet function that is going to
// greet people using the Strategy passed to the constructor.
Greeter.prototype.greet = function() {
  return this.strategy();
};

// Since a function encapsulates an algorithm, it makes a perfect
// candidate for a Strategy.
//
// Here are a couple of Strategies to use with our Greeter.
var politeGreetingStrategy = function() {
 console.log("Hello."); 
};

var friendlyGreetingStrategy = function() {
  console.log("Hey!");
};

var boredGreetingStrategy = function() {
  console.log("sup.");
};

// Let's use these strategies!
var politeGreeter   = new Greeter(politeGreetingStrategy);
var friendlyGreeter = new Greeter(friendlyGreetingStrategy);
var boredGreeter    = new Greeter(boredGreetingStrategy);

console.log(politeGreeter.greet());   //=> Hello.
console.log(friendlyGreeter.greet()); //=> Hey!
console.log(boredGreeter.greet());    //=> sup.

Agreed with @paufraces those extra logs are redundant