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

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,
        };
    });

其他回答

我不认为顺序是可以保证的,否则就很容易切片Object的后半部分。条目的结果和映射来自那里。

上述答案的唯一(非常小的)问题是

字符串和数字之间有很多不必要的类型转换。 当一次迭代同样干净有效时,条目将迭代两次。

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

function enumToList<T extends StandardEnum> (enm: T) : { id: number; description: string }[] {
    return Object.entries(enm).reduce((accum, kv) => {
        if (typeof kv[1] === 'number') {
            accum.push({ id: kv[1], description: kv[0] })
        }
        return accum
    }, []) // if enum is huge, perhaps pre-allocate with new Array(entries.length / 2), however then push won't work, so tracking an index would also be required
}

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

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。

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]
  );
}

我从几个月前就了解了typescript,下面的解决方案对我来说很有效。希望它也能帮助到一些人

export enum ScheduleType {
  Basic = <any>'B',
  Consolidated = <any>'C',
}

scheduleTypes = Object.keys(ScheduleType)
.filter((k, i) => i % 2)
.map((key: any) => {
  return {
    systemValue: key,
    displayValue: ScheduleType[key],
  };
});

它给出了如下的结果- [{displayValue: "Basic", systemValue: "B"}, {displayValue: "Consolidated", systemValue: "C"}]