अगला, हम उदाहरणों को देखेंगे कि कैसे मैं जावास्क्रिप्ट में स्ट्रैटेजी का उपयोग करता हूं, और यह कैसे एक वास्तविक पुस्तकालय द्वारा उपयोग किया जाता है, इसे छोटे भागों में तोड़ने के लिए।

• रणनीति एक वस्तु है जो एक एल्गोरिथ्म को एन्क्रिप्ट करती है।
• क्लाइंट (या संदर्भ ) - एक ऐसी वस्तु जो किसी भी प्लग-एंड-प्ले प्लग-एंड-प्ले रणनीति का उपयोग कर सकती है।

एक समारोह के रूप में रणनीति

// Greeter -  ,    . //         var Greeter = function(strategy) { this.strategy = strategy; }; // Greeter   greet, //       //  ,    Greeter.prototype.greet = function() { return this.strategy(); }; //     , //       //  : var politeGreetingStrategy = function() { console.log("Hello."); }; var friendlyGreetingStrategy = function() { console.log("Hey!"); }; var boredGreetingStrategy = function() { console.log("sup."); }; //   ! 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. 

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

एक वर्ग के रूप में रणनीति

 var Greeter = function(strategy) { this.strategy = strategy; }; 

 //       Javascript //   ,      //     , //          . //    ,      var Strategy = function() {}; Strategy.prototype.execute = function() { throw new Error('Strategy#execute needs to be overridden.') }; //           //        `Strategy`. //  ,    , //      `execute` var GreetingStrategy = function() {}; GreetingStrategy.prototype = Object.create(Strategy.prototype); //   `execute`,       //    `Strategy`   . //  ,       . //      (Template Method). //      . GreetingStrategy.prototype.execute = function() { return this.sayHi() + this.sayBye(); }; GreetingStrategy.prototype.sayHi = function() { return "Hello, "; }; GreetingStrategy.prototype.sayBye = function() { return "Goodbye."; }; //      . //    -   `Greeter`. Greeter.prototype.greet = function() { return this.strategy.execute(); }; var greeter = new Greeter(new GreetingStrategy()); greeter.greet() //=> 'Hello, Goodbye.' 

 //   GreetingStrategy#execute    . //    ,     , //       ( `execute`) var PoliteGreetingStrategy = function() {}; PoliteGreetingStrategy.prototype = Object.create(GreetingStrategy.prototype); PoliteGreetingStrategy.prototype.sayHi = function() { return "Welcome sir, "; }; var FriendlyGreetingStrategy = function() {}; FriendlyGreetingStrategy.prototype = Object.create(GreetingStrategy.prototype); FriendlyGreetingStrategy.prototype.sayHi = function() { return "Hey, "; }; var BoredGreetingStrategy = function() {}; BoredGreetingStrategy.prototype = Object.create(GreetingStrategy.prototype); BoredGreetingStrategy.prototype.sayHi = function() { return "sup, "; }; var politeGreeter = new Greeter(new PoliteGreetingStrategy()); var friendlyGreeter = new Greeter(new FriendlyGreetingStrategy()); var boredGreeter = new Greeter(new BoredGreetingStrategy()); politeGreeter.greet(); //=> 'Welcome sir, Goodbye.' friendlyGreeter.greet(); //=> 'Hey, Goodbye.' boredGreeter.greet(); //=> 'sup, Goodbye.' 

 var greeters = [ new Greeter(new BoredGreetingStrategy()), new Greeter(new PoliteGreetingStrategy()), new Greeter(new FriendlyGreetingStrategy()), ]; greeters.forEach(function(greeter) { //    `greeter`     //      . //      `greet`, //        . greeter.greet(); }); 

वास्तविक कोड में संरचना

 //    http://passportjs.org var passport = require('passport') //      npm-. //     . , LocalStrategy = require('passport-local').Strategy , FacebookStrategy = require('passport-facebook').Strategy; // Passport      . passport.use(new LocalStrategy( function(username, password, done) { User.findOne({ username: username }, function (err, user) { if (err) { return done(err); } if (!user) { return done(null, false, { message: 'Incorrect username.' }); } if (!user.validPassword(password)) { return done(null, false, { message: 'Incorrect password.' }); } return done(null, user); }); } )); // ,    Facebook passport.use(new FacebookStrategy({ clientID: FACEBOOK_APP_ID, clientSecret: FACEBOOK_APP_SECRET, callbackURL: "http://www.example.com/auth/facebook/callback" }, function(accessToken, refreshToken, profile, done) { User.findOrCreate(..., function(err, user) { if (err) { return done(err); } done(null, user); }); } )); 

नैतिकता