ES6 Language Specification
2018-06-15 本文已影响0人
yaoyuquan
EMCA数据类型和value
undefined
null
boolean
String
Number
Symbol
The Symbol type is the set of all non-String values that may be used as the key of an Object property (6.1.7).
Each possible Symbol value is unique and immutable.
Each Symbol value immutably holds an associated value called [[Description]] that is
either undefined or a String value.
Object
