log method calls of an arbitrary JavaScript object

logify.js

var Class = function() {
	this.test = 'hi';
}

Class.prototype.testfunc = function(arg1, arg2) {
	console.log(arg1 + arg2);
}

function logify(obj, name) {
	var proto = Object.getPrototypeOf(obj);
	Object.getOwnPropertyNames(proto).forEach(function(key) {
		if (typeof proto[key] === 'function') {
			var fn = proto[key];
			proto[key] = function() {
				console.log(name + '.' + key + '(' + Array.prototype.join.call(arguments, ',') + ')');
				fn.apply(obj, arguments);
			}
		}
	});
}

var inst = new Class();
logify(inst, 'inst');
inst.testfunc('hi ', 'guys');