如果你想让它与字符串ENUM一起工作，你需要使用Object.values(ENUM).includes(enumenumvalue)，因为字符串ENUM不是反向映射的，根据https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-4.html:

enum Vehicle {
    Car = 'car',
    Bike = 'bike',
    Truck = 'truck'
}

就变成:

{
    Car: 'car',
    Bike: 'bike',
    Truck: 'truck'
}

所以你只需要做:

if (Object.values(Vehicle).includes('car')) {
    // Do stuff here
}

如果你得到一个错误:属性“values”在类型“ObjectConstructor”上不存在，那么你不是针对ES2017。您可以使用这个tsconfig。json配置:

"compilerOptions": {
    "lib": ["es2017"]
}

或者你可以做任意类型的转换:

if ((<any>Object).values(Vehicle).includes('car')) {
    // Do stuff here
}

enum ServicePlatform {
    UPLAY = "uplay",
    PSN = "psn",
    XBL = "xbl"
}

就变成:

{ UPLAY: 'uplay', PSN: 'psn', XBL: 'xbl' }

so

ServicePlatform.UPLAY in ServicePlatform // false

解决方案:

ServicePlatform.UPLAY.toUpperCase() in ServicePlatform // true

对于你的问题，有一个非常简单易行的解决方法:

var districtId = 210;

if (DistrictsEnum[districtId] != null) {

// Returns 'undefined' if the districtId not exists in the DistrictsEnum 
    model.handlingDistrictId = districtId;
}

export enum UserLevel {
  Staff = 0,
  Leader,
  Manager,
}

export enum Gender {
  None = "none",
  Male = "male",
  Female = "female",
}

log中的差异结果:

log(Object.keys(Gender))
=>
[ 'None', 'Male', 'Female' ]

log(Object.keys(UserLevel))
=>
[ '0', '1', '2', 'Staff', 'Leader', 'Manager' ]

解决方案，我们需要删除键作为一个数字。

export class Util {
  static existValueInEnum(type: any, value: any): boolean {
    return Object.keys(type).filter(k => isNaN(Number(k))).filter(k => type[k] === value).length > 0;
  }
}

使用

// For string value
if (!Util.existValueInEnum(Gender, "XYZ")) {
  //todo
}

//For number value, remember cast to Number using Number(val)
if (!Util.existValueInEnum(UserLevel, 0)) {
  //todo
}

如果你在那里找不到如何检查联合包含的具体值，有解决方案:

// source enum type
export const EMessagaType = {
   Info,
   Success,
   Warning,
   Error,
};

//check helper
const isUnionHasValue = <T extends number>(union: T, value: T) =>
   (union & value) === value;


//tests
console.log(
 isUnionHasValue(EMessagaType.Info | EMessagaType.Success), 
 EMessagaType.Success);

//output: true


console.log(
 isUnionHasValue(EMessagaType.Info | EMessagaType.Success), 
 EMessagaType.Error); 

//output: false

更新:

我发现，每当我需要检查一个值是否存在于枚举中，我并不真的需要枚举，类型是一个更好的解决方案。所以我原来答案中的enum变成:

export type ValidColors =
  | "red"
  | "orange"
  | "yellow"
  | "green"
  | "blue"
  | "purple";

最初的回答:

为了清晰起见，我喜欢将值分开，并将调用包含在单独的行上。这里有一个例子:

export enum ValidColors {
  Red = "red",
  Orange = "orange",
  Yellow = "yellow",
  Green = "green",
  Blue = "blue",
  Purple = "purple",
}

function isValidColor(color: string): boolean {
  const options: string[] = Object.values(ValidColors);
  return options.includes(color);
}