javascript - 在JavaScript中定义枚举的首选语法是什么？ [关闭](What is the preferred syntax for defining enums in JavaScript? [closed])

Question

What is the preferred syntax for defining enums in JavaScript?(在JavaScript中定义枚举的首选语法是什么？)

Something like:(就像是：)

my.namespace.ColorEnum = {
    RED : 0,
    GREEN : 1,
    BLUE : 2
}

// later on

if(currentColor == my.namespace.ColorEnum.RED) {
   // whatever
}

Or is there a more preferable idiom?(还是有更好的成语？)

  ask by David Citron translate from so

Answer 1

Since 1.8.5 it's possible to seal and freeze the object, so define the above as:(从1.8.5开始，可以密封和冻结对象，因此将以上定义为：)

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

or(要么)

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

and voila!(和瞧！)

JS enums.(JS枚举。)

However, this doesn't prevent you from assigning an undesired value to a variable, which is often the main goal of enums:(但是，这不会阻止您将不想要的值分配给变量，这通常是枚举的主要目标：)

let day = DaysEnum.tuesday
day = 298832342 // goes through without any errors

One way to ensure a stronger degree of type safety (with enums or otherwise) is to use a tool like TypeScript or Flow .(确保类型安全性（使用枚举或其他方式）的程度更高的一种方法是使用诸如TypeScript或Flow之类的工具。)

Source(资源)

Quotes aren't needed but I kept them for consistency.(不需要引号，但为了保持一致性，我保留了它们。)