A simple example of the "switch" code smell

CreditCard-complex-functional.js

function CreditCard(http) {
	this.process = function(cardType, cardNumber) {
		var cardProcessor = { 
			"VISA": 	  this.processVisa,
			"MASTERCARD":     this.processMasterCard,
			"AMEX": 	  this.processAmex
		};
		cardProcessor[cardType](cardNumber);
	};
	this.processVisa = function(cardNumber) {
		var trimmedCardNumber=cardNumber.replace(/\s/g,'');
		if (trimmedCardNumber.length!==16) {
			throw new Error("Invalid card number");
		}
		if(trimmedCardNumber[0]!=='4') {
			throw new Error("Invalid card number");
		}
		http.POST('http://visa.com', { "cardNumber": cardNumber});
	};
	this.processMasterCard = function(cardNumber) {
		var trimmedCardNumber=cardNumber.replace(/\s/g,'');
		if (trimmedCardNumber.length!==16) {
			throw new Error("Invalid card number");
		}
		if(trimmedCardNumber[0]!=='5') {
			throw new Error("Invalid card number");
		}
		http.POST('http://mastercard.com', { "cardNumber": cardNumber});
	};
	this.processAmex = function(cardNumber) {
		var trimmedCardNumber=cardNumber.replace(/\s/g,'');
		if (trimmedCardNumber.length!==15) {
			throw new Error("Invalid card number");
		}
		if(trimmedCardNumber[0]!=='3') {
			throw new Error("Invalid card number");
		}
		http.POST('http://amex.com', { "cardNumber": cardNumber});
	};
};

CreditCard-complex-strategy.js

function CreditCardStrategy(http) {
	this.http = http;
	this.process = function(cardType, cardNumber) {
		cardProcessor = { 
				"VISA": 	new VisaCreditCardProcessor(this.http),
				"MASTERCARD": 	new MasterCardCreditCardProcessor(this.http),
				"AMEX": 	new AmexCreditCardProcessor(this.http)
		};
		cardProcessor[cardType].process(cardNumber);
	};
};

function CreditCardProcessor(http) {
	this.http = http;
	this.getUrl = function() {
		throw {"message": "must override"};
	};
	this.validate = function(cardNumber) {
		throw {"message": "must override"};
	};
	this.process = function(cardNumber) { 
		this.validate(cardNumber);
		this.http.POST(this.getUrl(), { "cardNumber": cardNumber});
	};
};

function VisaCreditCardProcessor(http) {
	CreditCardProcessor.call(this, http);
	this.getUrl = function() { 
		return 'http://visa.com';
	};
	this.validate = function(cardNumber) {
		var trimmedCardNumber=cardNumber.replace(/\s/g,'');
		if (trimmedCardNumber.length!==16) {
			throw new Error("Invalid card number");
		}
		if(trimmedCardNumber[0]!=='4') {
			throw new Error("Invalid card number");
		}
	};
}

function MasterCardCreditCardProcessor(http) {
	CreditCardProcessor.call(this, http);
	this.getUrl = function() { 
		return 'http://mastercard.com';
	};
	this.validate = function(cardNumber) {
		var trimmedCardNumber=cardNumber.replace(/\s/g,'');
		if (trimmedCardNumber.length!==16) {
			throw new Error("Invalid card number");
		}
		if(trimmedCardNumber[0]!=='5') {
			throw new Error("Invalid card number");
		}
	};
}

function AmexCreditCardProcessor(http) {
	CreditCardProcessor.call(this, http);
	this.getUrl = function() { 
		return 'http://amex.com';
	};
	this.validate = function(cardNumber) {
		var trimmedCardNumber=cardNumber.replace(/\s/g,'');
		if (trimmedCardNumber.length!==15) {
			throw new Error("Invalid card number");
		}
		if(trimmedCardNumber[0]!=='3') {
			throw new Error("Invalid card number");
		}
	};
}

CreditCard-simple-functional.js

function CreditCard(http) {
	this.process = function(cardType, cardNumber) {
		var cardProcessor = { 
			"VISA": 	  this.processVisa,
			"MASTERCARD":     this.processMasterCard,
			"AMEX": 	  this.processAmex
		};
		cardProcessor[cardType](cardNumber);
	};
	this.processVisa = function(cardNumber) {
		http.POST('http://visa.com', { "cardNumber": cardNumber});
	};
	this.processMasterCard = function(cardNumber) {
		http.POST('http://mastercard.com', { "cardNumber": cardNumber});
	};
	this.processAmex = function(cardNumber) {
		http.POST('http://amex.com', { "cardNumber": cardNumber});
	};
};

CreditCard-simple-strategy.js

function CreditCard(http) {
	this.http = http;
	this.process = function(cardType, cardNumber) {
		cardProcessor = { 
				"VISA":       new VisaCreditCardProcessor(this.http),
				"MASTERCARD": new MasterCardCreditCardProcessor(this.http),
				"AMEX":       new AmexCreditCardProcessor(this.http)
		};
		cardProcessor[cardType].process(cardNumber);
	};
};

function CreditCardProcessor(http) {
	this.http = http;
	this.getUrl = function() {
		throw {"message": "must override"};
	};
	this.process = function(cardNumber) { 
		this.http.POST(this.getUrl(), { "cardNumber": cardNumber});
	};
};

function VisaCreditCardProcessor(http) {
	CreditCardProcessor.call(this, http);
	this.getUrl = function() { 
		return 'http://visa.com';
	};
}

function MasterCardCreditCardProcessor(http) {
	CreditCardProcessor.call(this, http);
	this.getUrl = function() { 
		return 'http://mastercard.com';
	};
}

function AmexCreditCardProcessor(http) {
	CreditCardProcessor.call(this, http);
	this.getUrl = function() { 
		return 'http://amex.com';
	};
}

CreditCard-simple-switch.js

function CreditCard(http) {
  this.http = http;
  this.process = function(cardType, cardNumber) {
    switch(cardType) {
	case "VISA":
  	  this.http.POST('http://visa.com', { "cardNumber": cardNumber});
	  break;
	case "MASTERCARD":
	  this.http.POST('http://mastercard.com', {"cardNumber": cardNumber});
	  break;
	case "AMEX":
	  this.http.POST('http://amex.com', {"cardNumber": cardNumber});
	  break;
     }
  };
};