debugmodedotnet/objectfressze5.js

## objectfressze5.js
'use strict'
var cat = {

    name:'foo',
    age: 9
}

Object.preventExtensions(cat);
cat.color ='black';
console.log(cat.color); // error thrown
	'use strict'
	var cat = {

	name:'foo',
	age: 9
	}

	Object.preventExtensions(cat);
	cat.color ='black';
	console.log(cat.color); // error thrown