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

这个解决方案也可以。

enum ScreenType {
    Edit = 1,
    New = 2,
    View = 4
}

var type: ScreenType = ScreenType.Edit;

console.log(ScreenType[type]); //Edit

其他回答

虽然答案已经提供了,但几乎没有人指向文档

下面是一个片段

enum Enum {
    A
}
let nameOfA = Enum[Enum.A]; // "A"

请记住,string enum成员根本不会生成反向映射。

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" ];

我希望这个问题仍然有意义。我使用这样的函数:

function enumKeys(target: Record<string, number|string>): string[] {
  const allKeys: string[] = Object.keys(target);
  const parsedKeys: string[] = [];

  for (const key of allKeys) {
    const needToIgnore: boolean
      = target[target[key]]?.toString() === key && !isNaN(parseInt(key));

    if (!needToIgnore) {
      parsedKeys.push(key);
    }
  }

  return parsedKeys;
}

function enumValues(target: Record<string, number|string>): Array<string|number> {
  const keys: string[] = enumKeys(target);
  const values: Array<string|number> = [];

  for (const key of keys) {
    values.push(target[key]);
  }

  return values;
}

例子:

enum HttpStatus {
  OK,
  INTERNAL_ERROR,
  FORBIDDEN = 'FORBIDDEN',
  NOT_FOUND = 404,
  BAD_GATEWAY = 'bad-gateway'
}


console.log(enumKeys(HttpStatus));
// > ["OK", "INTERNAL_ERROR", "FORBIDDEN", "NOT_FOUND", "BAD_GATEWAY"] 

console.log(enumValues(HttpStatus));
// > [0, 1, "FORBIDDEN", 404, "bad-gateway"]

我通过搜索“TypeScript iterate over enum keys”找到了这个问题。所以我只想给出对我来说有用的解。也许对别人也有帮助。

我的情况如下:我想在每个枚举键上迭代,然后过滤一些键,然后访问一些对象,其中键作为枚举的计算值。这就是没有TS误差的方法。

    enum MyEnum = { ONE = 'ONE', TWO = 'TWO' }
    const LABELS = {
       [MyEnum.ONE]: 'Label one',
       [MyEnum.TWO]: 'Label two'
    }


    // to declare type is important - otherwise TS complains on LABELS[type]
    // also, if replace Object.values with Object.keys - 
    // - TS blames wrong types here: "string[] is not assignable to MyEnum[]"
    const allKeys: Array<MyEnum> = Object.values(MyEnum)

    const allowedKeys = allKeys.filter(
      (type) => type !== MyEnum.ONE
    )

    const allowedLabels = allowedKeys.map((type) => ({
      label: LABELS[type]
    }))

我看不正确的答案看累了,就自己做了。

这个有测试。 适用于所有类型的枚举。 正确地输入。

type EnumKeys<Enum> = Exclude<keyof Enum, number>

const enumObject = <Enum extends Record<string, number | string>>(e: Enum) => {
    const copy = {...e} as { [K in EnumKeys<Enum>]: Enum[K] };
    Object.values(e).forEach(value => typeof value === 'number' && delete copy[value]);
    return copy;
};

const enumKeys = <Enum extends Record<string, number | string>>(e: Enum) => {
    return Object.keys(enumObject(e)) as EnumKeys<Enum>[];
};

const enumValues = <Enum extends Record<string, number | string>>(e: Enum) => {
    return [...new Set(Object.values(enumObject(e)))] as Enum[EnumKeys<Enum>][];
};

enum Test1 { A = "C", B = "D"}
enum Test2 { A, B }
enum Test3 { A = 0, B = "C" }
enum Test4 { A = "0", B = "C" }
enum Test5 { undefined = "A" }
enum Test6 { A = "undefined" }
enum Test7 { A, B = "A" }
enum Test8 { A = "A", B = "A" }
enum Test9 { A = "B", B = "A" }

console.log(enumObject(Test1)); // {A: "C", B: "D"}
console.log(enumObject(Test2)); // {A: 0, B: 1}
console.log(enumObject(Test3)); // {A: 0, B: "C"}
console.log(enumObject(Test4)); // {A: "0", B: "C"}
console.log(enumObject(Test5)); // {undefined: "A"}
console.log(enumObject(Test6)); // {A: "undefined"}
console.log(enumObject(Test7)); // {A: 0,B: "A"}
console.log(enumObject(Test8)); // {A: "A", B: "A"}
console.log(enumObject(Test9)); // {A: "B", B: "A"}

console.log(enumKeys(Test1)); // ["A", "B"]
console.log(enumKeys(Test2)); // ["A", "B"]
console.log(enumKeys(Test3)); // ["A", "B"]
console.log(enumKeys(Test4)); // ["A", "B"]
console.log(enumKeys(Test5)); // ["undefined"]
console.log(enumKeys(Test6)); // ["A"]
console.log(enumKeys(Test7)); // ["A", "B"]
console.log(enumKeys(Test8)); // ["A", "B"]
console.log(enumKeys(Test9)); // ["A", "B"]

console.log(enumValues(Test1)); // ["C", "D"]
console.log(enumValues(Test2)); // [0, 1]
console.log(enumValues(Test3)); // [0, "C"]
console.log(enumValues(Test4)); // ["0", "C"]
console.log(enumValues(Test5)); // ["A"] 
console.log(enumValues(Test6)); // ["undefined"] 
console.log(enumValues(Test7)); // [0, "A"]
console.log(enumValues(Test8)); // ["A"]
console.log(enumValues(Test9)); // ["B", "A"]

在线版本。