我想迭代一个TypeScript枚举对象,并获得每个枚举符号名称,例如: enum myEnum {entry1, entry2}

for (var entry in myEnum) { 
    // use entry's name here, e.g., "entry1"
}

当前回答

唯一的解决方案,适用于我在所有情况下(即使值是字符串)是以下:

var enumToString = function(enumType, enumValue) {
    for (var enumMember in enumType) {
        if (enumType[enumMember]==enumValue) return enumMember
    }
}

其他回答

如果你只搜索名称,然后迭代使用:

Object.keys(myEnum).map(key => myEnum[key]).filter(value => typeof value === 'string') as string[];

根据TypeScript文档,我们可以通过Enum和静态函数来实现这一点。

使用静态函数获取Enum名称

enum myEnum { 
    entry1, 
    entry2 
}

namespace myEnum {
    export function GetmyEnumName(m: myEnum) {
      return myEnum[m];
    }
}


now we can call it like below
myEnum.GetmyEnumName(myEnum.entry1);
// result entry1 

要阅读更多关于Enum的静态函数,请点击下面的链接 https://basarat.gitbooks.io/typescript/docs/enums.html

在当前的TypeScript版本1.8.9中,我使用类型化enum:

export enum Option {
    OPTION1 = <any>'this is option 1',
    OPTION2 = <any>'this is option 2'
}

与结果在这个Javascript对象:

Option = {
    "OPTION1": "this is option 1",
    "OPTION2": "this is option 2",
    "this is option 1": "OPTION1",
    "this is option 2": "OPTION2"
}

所以我必须通过键和值查询,只返回值:

let optionNames: Array<any> = [];    
for (let enumValue in Option) {
    let optionNameLength = optionNames.length;

    if (optionNameLength === 0) {
        this.optionNames.push([enumValue, Option[enumValue]]);
    } else {
        if (this.optionNames[optionNameLength - 1][1] !== enumValue) {
            this.optionNames.push([enumValue, Option[enumValue]]);
        }
    }
}

我在数组中收到选项键:

optionNames = [ "OPTION1", "OPTION2" ];

我的Enum是这样的:

export enum UserSorting {
    SortByFullName = "Sort by FullName", 
    SortByLastname = "Sort by Lastame", 
    SortByEmail = "Sort by Email", 
    SortByRoleName = "Sort by Role", 
    SortByCreatedAt = "Sort by Creation date", 
    SortByCreatedBy = "Sort by Author", 
    SortByUpdatedAt = "Sort by Edit date", 
    SortByUpdatedBy = "Sort by Editor", 
}

这样做会返回undefined:

UserSorting[UserSorting.SortByUpdatedAt]

为了解决这个问题,我选择了另一种使用管道的方法:

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
    name: 'enumKey'
})
export class EnumKeyPipe implements PipeTransform {

  transform(value, args: string[] = null): any {
    let enumValue = args[0];
    var keys = Object.keys(value);
    var values = Object.values(value);
    for (var i = 0; i < keys.length; i++) {
      if (values[i] == enumValue) {
        return keys[i];
      }
    }
    return null;
    }
}

要使用它:

return this.enumKeyPipe.transform(UserSorting, [UserSorting.SortByUpdatedAt]);

我卑微的2美分基于阅读一个了不起的评论从github TS讨论

const EnvironmentVariants = ['development', 'production', 'test'] as const 
type EPredefinedEnvironment = typeof EnvironmentVariants[number]

然后在编译时:

// TS2322: Type '"qaEnv"' is not assignable to type '"development" | "production" | "test"'.
const qaEnv: EPredefinedEnvironment = 'qa' 

在运行时:

function isPredefinedEnvironemt(env: string) {
  for (const predefined of EnvironmentVariants) {
    if (predefined === env) {
      return true
    }
  }
  return false
}

assert(isPredefinedEnvironemet('test'), true)
assert(isPredefinedEnvironemet('qa'), false)

注意,for(const index in environmentvariables){…}将遍历"0","1","2"集合