有没有办法在Javascript中拥有/锁定Enum对象的唯一索引值？ [英] Is there a way to have/lock unique index values of the Enum object in Javascript?

问题描述

阅读推荐方式处理 ENUM类型在Javascript中，我仍然不确定，因为我可以将值与伪造值进行比较，而我只需要比较一个枚举类型值：

Reading the "recommended way" of dealing with ENUM Type in Javascript, I am still uncertain because I can compare the value with a forged value, while I should compare only to a "enum" type value:

 var DaysEnum = {"monday":1, "tuesday":2, "wednesday":3, ...}
 Object.freeze(DaysEnum)

 switch( day ){
   case "monday":
     return "Hello"
   case "tuesday":
     return "Hi"
   case "blahblahday":
     return "No"
 }

我将转换为（星期一，星期二，blahblahday）的字符串完全免于我的枚举类型：DaysEnum，可以由用户，这可能会导致一些未被解释器发现的微妙错误（如打字错误）。

The strings I made the switch to compare against ("monday", "tuesday", "blahblahday") are totally free from my "enum type: DaysEnum", can be provided by the user and this could lead to some subtle errors not spotted by the interpreter (like typos).

有没有办法拥有/锁定唯一的ind枚举对象的ex值？

Is there a way to have/lock unique index values of the Enum object?

推荐答案

使用ES2015发现的一个可能的解决方案可能是通过符号

A possible solution I found with ES2015 could be through Symbols

http://putaindecode.io/en/articles/ js / es2015 / symbols /

这样你就可以拥有独特的锁定值，就像您在其他语言中一样，像Java

This way you have the unique "locked" values, like you have in other languages, like Java

 const DAY_MONDAY = Symbol();
 const DAY_TUESDAY = Symbol();

 switch(animal) {
   case DAY_MONDAY:
     return "Hello"
   case DAY_TUESDAY:
     return "Hi"
   //there is no way you can go wrong with DAY_BLAHBLAHDAY 
   //the compiler will notice it and throw an error
 }

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