proxy下面3个是什么意思,是原型吗,为什么有2个方括号?

2 个回答

发布于
2019-10-21

Internal slots correspond to internal state that is associated with objects and used by various ECMAScript specification algorithms. Internal slots are not object properties and they are not inherited. Depending upon the specific internal slot specification, such state may consist of values of any ECMAScript language type or of specific ECMAScript specification type values. Unless explicitly specified otherwise, internal slots are allocated as part of the process of creating an object and may not be dynamically added to an object. Unless specified otherwise, the initial value of an internal slot is the value undefined. Various algorithms within this specification create objects that have internal slots. However, the ECMAScript language provides no direct way to associate internal slots with an object.
Internal methods and internal slots are identified within this specification using names enclosed in double square brackets [[ ]].

ECMA262 为了维护对象的内部状态引入的一些“内置槽”。他们不是对象属性，程序员无法直接操作。