对象常量
var myObject = {};
Object.defineProperty( myObject, "FAVORITE_NUMBER", {
value: 42,
writable: false,
configurable: false
} );
var myObject = {
a: 2
};
Object.preventExtensions( myObject );
myObject.b = 3;
myObject.b; // undefined
使用preventExtensions方法,可禁止对象再次扩展。
Object.seal(..)
preventExtensions + configurable:false
Object.freeze(..)
s Object.seal(..) + writable:false