我有一个这样定义的枚举:

export enum GoalProgressMeasurements {
    Percentage = 1,
    Numeric_Target = 2,
    Completed_Tasks = 3,
    Average_Milestone_Progress = 4,
    Not_Measured = 5
}

然而,我希望它被表示为一个对象数组/列表从我们的API如下:

[{id: 1, name: 'Percentage'}, 
 {id: 2, name: 'Numeric Target'},
 {id: 3, name: 'Completed Tasks'},
 {id: 4, name: 'Average Milestone Progress'},
 {id: 5, name: 'Not Measured'}]

是否有简单和本地的方法来做到这一点,或者我必须构建一个函数,将枚举转换为int和字符串,并将对象构建为数组?


当前回答

由于具有字符串值的枚举不同于具有数字值的枚举,因此最好从@user8363解决方案中过滤非数字。

这里是你如何从enum字符串中获取值,数字混合:

/ /帮助 export const StringIsNotNumber = value => isNaN(Number(value)) === true; //将枚举转换为数组 导出函数enumToArray(枚举){ 返回种(enumme) .filter (StringIsNotNumber) .map(key => enumme[key]); }

其他回答

我很惊讶,在一个TypeScript线程中,没有人给出支持类型的有效TypeScript函数。下面是@user8363解决方案的变化:

const isStringNumber = (value: string) => isNaN(Number(value)) === false;

function enumToArray<T extends {}>(givenEnum: T) {
  return (Object.keys(givenEnum).filter(isStringNumber) as (keyof T)[]).map(
    (key) => givenEnum[key]
  );
}

我不喜欢上面的答案,因为它们都不能正确地处理字符串/数字的混合,可以在TypeScript enum中作为值。

下面的函数遵循TypeScript枚举的语义,给出键到值的正确映射。从那里,获取一个对象数组或者仅仅是键或者仅仅是值是很简单的。

/**
 * Converts the given enum to a map of the keys to the values.
 * @param enumeration The enum to convert to a map.
 */
function enumToMap(enumeration: any): Map<string, string | number> {
  const map = new Map<string, string | number>();
  for (let key in enumeration) {
      //TypeScript does not allow enum keys to be numeric
      if (!isNaN(Number(key))) continue;

      const val = enumeration[key] as string | number;

      //TypeScript does not allow enum value to be null or undefined
      if (val !== undefined && val !== null)
          map.set(key, val);
  }

  return map;
}

使用示例:

enum Dog {
    Rover = 1,
    Lassie = "Collie",
    Fido = 3,
    Cody = "Mutt",
}

let map = enumToMap(Dog); //Map of keys to values

let objs = Array.from(map.entries()).map(m => ({id: m[1], name: m[0]})); //Objects as asked for in OP
let entries = Array.from(map.entries()); //Array of each entry
let keys = Array.from(map.keys()); //An array of keys
let values = Array.from(map.values()); //An array of values

我还要指出OP是逆向思考枚举的。枚举中的“键”在技术上是在左边,而值在右边。TypeScript允许你尽可能多地重复RHS上的值。

如果你使用的是ES8

只有在这种情况下,它才会工作得很好。它会给你给定枚举的值数组。

enum Colors {
  WHITE = 0,
  BLACK = 1,
  BLUE = 3
}

const colorValueArray = Object.values(Colors); //[ 'WHITE', 'BLACK', 'BLUE', 0, 1, 3 ]

你会得到这样的colorValueArray ['WHITE', 'BLACK', 'BLUE', 0,1,3]。所有的键都在数组的前半部分,所有的值都在数组的后半部分。

甚至这种枚举也可以正常工作

enum Operation {
    READ,
    WRITE,
    EXECUTE
}

但是这种解决方案不适用于这样的异构枚举

enum BooleanLikeHeterogeneousEnum {
  No = 0,
  Yes = "YES",
}

该方法基于语句: enum的键不能是数字

export const isNumeric = (num?: Value | null): num is number => {
  if (num === undefined || num === null) {
    return false;
  } 
  
  const number = +num;

  if (number - number !== 0) {
    // Discard Infinity and NaN
    return false;
  }

  if (number === num) {
    return true;
  }

  if (typeof num === 'string') {
    return !(number === 0 && num.trim() === '');
  }
  return false;
};

enum En  {
  ewq1 = 1,
  we2 = 'ss',
  sad = 'sad',
}

type TEnum = {
    [id: string]: number | string;
}

export const getEnumValues = <T extends TEnum>(enumerable: T) =>
  Object.keys(enumerable)
    .filter((x) => !isNumeric(x))
    .map((key) => enumerable[key] as T[keyof T]) 

console.log(getEnumValues(En)) // [1, "ss", "sad"] 

你可以这样做:

export enum GoalProgressMeasurements {
    Percentage = 1,
    Numeric_Target = 2,
    Completed_Tasks = 3,
    Average_Milestone_Progress = 4,
    Not_Measured = 5
}

export class GoalProgressMeasurement {
    constructor(public goalProgressMeasurement: GoalProgressMeasurements, public name: string) {
    }
}

export var goalProgressMeasurements: { [key: number]: GoalProgressMeasurement } = {
    1: new GoalProgressMeasurement(GoalProgressMeasurements.Percentage, "Percentage"),
    2: new GoalProgressMeasurement(GoalProgressMeasurements.Numeric_Target, "Numeric Target"),
    3: new GoalProgressMeasurement(GoalProgressMeasurements.Completed_Tasks, "Completed Tasks"),
    4: new GoalProgressMeasurement(GoalProgressMeasurements.Average_Milestone_Progress, "Average Milestone Progress"),
    5: new GoalProgressMeasurement(GoalProgressMeasurements.Not_Measured, "Not Measured"),
}

你可以这样使用它:

var gpm: GoalProgressMeasurement = goalProgressMeasurements[GoalProgressMeasurements.Percentage];
var gpmName: string = gpm.name;

var myProgressId: number = 1; // the value can come out of drop down selected value or from back-end , so you can imagine the way of using
var gpm2: GoalProgressMeasurement = goalProgressMeasurements[myProgressId];
var gpmName: string = gpm.name;

您可以根据需要使用对象的附加属性扩展GoalProgressMeasurement。我将这种方法用于每个应该是包含多个值的对象的枚举。