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

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。

其他回答

enum目标进度测量{ 百分比= 1, Numeric_Target = 2, Completed_Tasks = 3, average_milestone one_progress = 4, Not_Measured = 5 } Const数组= [] for (const [key, value] of Object.entries(GoalProgressMeasurements)) { if (!Number. isnan (Number(key)) { 继续; } 数组中。Push ({id:值,名称:键。Replace ('_', ")}); } console.log(数组);

多亏了波尔科夫尼科夫。我终于能够找到一个解决方案,将工作的大多数用例。

问题的有效解

type Descripted<T> = {
    [K in keyof T]: {
        readonly id: T[K];
        readonly description: string;
    }
}[keyof T]

/**
 * Helper to produce an array of enum descriptors.
 * @param enumeration Enumeration object.
 * @param separatorRegex Regex that would catch the separator in your enum key.
 */
export function enumToDescriptedArray<T>(enumeration: T, separatorRegex: RegExp = /_/g): Descripted<T>[] {
    return (Object.keys(enumeration) as Array<keyof T>)
        .filter(key => isNaN(Number(key)))
        .filter(key => typeof enumeration[key] === "number" || typeof enumeration[key] === "string")
        .map(key => ({
            id: enumeration[key],
            description: String(key).replace(separatorRegex, ' '),
        }));
}

例子:


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

console.log(enumToDescriptedArray(GoalProgressMeasurements))
// Produces:
/*
[
    {id: 1, description: "Percentage"},
    {id: 2, description: "Numeric Target"},
    {id: 3, description: "Completed Tasks"},
    {id: 4, description: "Average Milestone Progress"},
    {id: 5, description: "Not Measured"}
]
*/

此外,我还使用了一个有用的util函数来将枚举对象映射到它拥有的可用值数组:

该映射器

type NonFunctional<T> = T extends Function ? never : T;

/**
 * Helper to produce an array of enum values.
 * @param enumeration Enumeration object.
 */
export function enumToArray<T>(enumeration: T): NonFunctional<T[keyof T]>[] {
    return Object.keys(enumeration)
        .filter(key => isNaN(Number(key)))
        .map(key => enumeration[key])
        .filter(val => typeof val === "number" || typeof val === "string");
}

用例工作

数字枚举

enum Colors1 {
    WHITE = 0,
    BLACK = 1
}
console.log(Object.values(Colors1)); // ['WHITE', 'BLACK', 0, 1]
console.log(enumToArray(Colors1));   // [0, 1]

字符串枚举

enum Colors2 {
    WHITE = "white",
    BLACK = "black"
}
console.log(Object.values(Colors2)); // ['white', 'black']
console.log(enumToArray(Colors2));   // ['white', 'black']

异构枚举

enum Colors4 {
    WHITE = "white",
    BLACK = 0
}
console.log(Object.values(Colors4)); // ["BLACK", "white", 0]
console.log(enumToArray(Colors4));   // ["white", 0]

与具有导出函数的命名空间合并的Enum


enum Colors3 {
    WHITE = "white",
    BLACK = "black"
}
namespace Colors3 {
    export function fun() {}
}
console.log(Object.values(Colors3)); // ['white', 'black', Function]
console.log(enumToArray(Colors3));   // ['white', 'black']

设enum变量为:

 enum EnumName {
      A = 1,
      B = 2
    };

那么列表是:

const list = Object.keys(Enum)
.filter((value => isNaN(Number(value)) === false))
      .map(key => ({ id: key, value: Enum[key] }));

list的值为

list = [ 
{ id:1 , value: A },
{ id:2 , value: B },
];

枚举是运行时存在的真实对象。所以你可以这样反向映射:

let value = GoalProgressMeasurements.Not_Measured;
console.log(GoalProgressMeasurements[value]);
// => Not_Measured

基于此,您可以使用以下代码:

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

let map: {id: number; name: string}[] = [];

for(var n in GoalProgressMeasurements) {
    if (typeof GoalProgressMeasurements[n] === 'number') {
        map.push({id: <any>GoalProgressMeasurements[n], name: n});
    }
}

console.log(map);

参考:https://www.typescriptlang.org/docs/handbook/enums.html

首先,我们得到这个枚举的键数组。然后,使用map()函数将数据转换为所需的格式。Id从键获取,name从enum通过相同的键获取。

const converted = Object.keys(GoalProgressMeasurements).map(key => {
        return {
            id: GoalProgressMeasurements[key],
            name: key,
        };
    });