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

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

其他回答

function enumKeys(_enum) {
  const entries = Object.entries(_enum).filter(e => !isNaN(Number(e[0])));
  if (!entries.length) {
    // enum has string values so we can use Object.keys
    return Object.keys(_enum);
  }
  return entries.map(e => e[1]);
}

另一种方法是使用ES8 Object.entries

export enum Weeks {  
    MONDAY = 1,  
    TUESDAY= 2,  
    WEDNESDAY = 3,  
    THURSDAY = 4,  
    FRIDAY = 5,  
    SATURDAY=6,  
    SUNDAY=7,  
}


function convertEnumToArray(){
   const arrayObjects = []            
     // Retrieve key and values using Object.entries() method. 
     for (const [propertyKey, propertyValue] of Object.entries(Weeks)) { 

      // Ignore keys that are not numbers
      if (!Number.isNaN(Number(propertyKey))) {  
        continue;  
      }  

      // Add keys and values to array
      arrayObjects.push({ id: propertyValue, name: propertyKey });  
    }        

  console.log(arrayObjects); 
}

将产生以下内容:

[ 
  { id: 1, name: 'MONDAY' },  
  { id: 2, name: 'TUESDAY' },  
  { id: 3, name: 'WEDNESDAY' },  
  { id: 4, name: 'THURSDAY' },  
  { id: 5, name: 'FRIDAY' },  
  { id: 6, name: 'SATURDAY' },  
  { id: 7, name: 'SUNDAY' } 
] 

无耻地从这个博客偷来的

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",
}

有一个简单的解决方案,当你运行object。Keys (Enum)它会给你一个值和键的数组,在第一个slice Values中,在第二个slice key中,为什么我们不直接返回第二个slice,下面的代码对我来说是有用的。

enum Enum {
   ONE,
   TWO,
   THREE,
   FOUR,
   FIVE,
   SIX,
   SEVEN
}
const keys = Object.keys(Enum); 
console.log(keys.slice(keys.length / 2));

只有一句话:

Object.entries(GoalProgressMeasurements).map(([key, value]) => ({id: key, value: value}))