Argument sanitization

example.js

// Module dependencies
var sanitize = require("./sanitize.js");

// function createConnection(String host, Number port, Object credentials, Array data) 
function createConnection(host, port, credentials, data) {
	sanitize(arguments, [String, Number, Object, Array]);
	
	console.log(host, port, credentials, data);
}

// Test it
// port, data, host, credentials -> host, port, credentials, data
createConnection(80, ["send this", "and this"], "localhost", { user: "silvinci", password: "secret" });

sanitize.js

// Expose sanitize
module.exports = exports = sanitize;
exports.typeOf = typeOf;
exports.nameOf = nameOf;

// Type check helpers
function typeOf(o) {
	return Object.prototype.toString.call(o).match(/(\w+)\]/)[1];
}
function nameOf(o) {
	return typeOf(o) == "Function"
		? Function.prototype.toString.call(o).match(/function (\w+)/)[1]
		: false;
}

// Sanitize arguments
function sanitize(args, order) {
	Array.prototype.slice.call(args).forEach(function(arg, oldIndex) {
		order.forEach(function(type, newIndex) {
			if(typeOf(arg) == nameOf(type)) args[newIndex] = arg;
		});
	});
	return args;
}

When using strict mode, you'll have to work with the returned array, since manipulating arguments is forbidden.