Node modules for basic type checking

ducktype.js

exports.isKindOf = function(duck, obj) {
	var fn = function(obj) {
		return Object.getOwnPropertyNames(duck).every(function(name) {
			return obj.hasOwnProperty(name);
		});
	};
	return obj === undefined ? fn : fn(obj);
};

typecheck.js

["Object", "String", "Number", "Boolean", "Array", "Date", "RegExp"].forEach(function(type) {
	exports["is" + type] = function(obj) {
		return Object.prototype.toString.apply(obj) === "[object " + type + "]";
	};
});