js_freeze.js

var frozenObject = {
    value1 : 1,
    value2 : 2
};
 
Object.freeze(frozenObject);
console.log(Object.isFrozen(frozenObject)); // true
 
// 삭제 불가
delete frozenObject.value1;
console.log(frozenObject.value1); // 1
 
// 변경 불가
frozenObject.value2 = 3;
console.log(frozenObject.value2); // 2
 
// 객체 추가 불가
frozenObject.value3 = 3;
console.log(frozenObject.value3); // undefined