[js] 防篡改对象

#preventExtensions

对象成员可修改、可删除，不可增加

 

            var person = {
                name: "Nicholas"
            };
            console.log(Object.isExtensible(person)); //true
            Object.preventExtensions(person);
            console.log(Object.isExtensible(person)); //false
            person.age = 29;
            console.log(person.age);//undefined
            person.name = 'husky';
            console.log(person.name);//husky
            delete person.name;
            console.log(person.name);//undefined,删除了

 

#seal

可修改，不可增加、不可删除

            var person = {
                name: "QM"
            };
            console.log(Object.isExtensible(person)); //true
            console.log(Object.isSealed(person)); //false
            Object.seal(person);
            console.log(Object.isExtensible(person)); //false
            console.log(Object.isSealed(person)); //true
            person.age = 29;
            console.log(person.age); //undefined
            person.name = 'husky';
            console.log(person.name);//husky
            delete person.name;
            console.log(person.name); //husky

 

#freeze

不可增加、不可修改、不可删除

            var person = {
                name: "Nicholas"
            };
            console.log(Object.isExtensible(person)); //true
            console.log(Object.isSealed(person)); //false
            console.log(Object.isFrozen(person)); //false
            Object.freeze(person);
            console.log(Object.isExtensible(person)); //false
            console.log(Object.isSealed(person)); //true
            console.log(Object.isFrozen(person)); //true
            person.age = 29;
            console.log(person.age); //undefined
            delete person.name;
            console.log(person.name); //"Nicholas"
            person.name = "Greg";
            console.log(person.name); //"Nicholas"