Type checking in javascript!

gistfile1.js

function type_checker() {
  var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
  function getParamNames(func) {
    var fnStr = func.toString().replace(STRIP_COMMENTS, '');
    var result = fnStr.slice(fnStr.indexOf('(')+1, fnStr.indexOf(')')).match(/([^\s,]+)/g);
    if(result === null)
       result = [];
    return result;
  }
  return function(types, func) {
    var args = getParamNames(func);
    return function() {
      var funcArgs = arguments;
      args.forEach(function(arg, i) {
        if (types[arg] !== funcArgs[i].constructor.name)
          throw 't TypeError ' + arg + ' expected ' + types[arg] + ' was ' + funcArgs[i].constructor.name
      });
      func.apply(this, arguments);
    }
  }
}

var t = type_checker();

// Example

t({name: 'String', age: 'Number'},
function greeting(name, age) {
  console.log('Hello ' + name + '. You\'re ' + age + ' years old');
});

function Cat() {}
Cat.prototype.hello = "Meow";

var greet = t({cat: 'Cat'},
function(cat) {
  console.log(cat.hello);
});

greet(new Cat()); // Meow
greet({hello: "Barf"}); // Throw: "t TypeError cat expected Cat was Object"

Nice :)