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]
);
}
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
}
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]
);
}
我是这样解的
const listKeys = Object.keys(TripStatus); //TripStatus is enum type
const numOfItem = listKeys.length/2;
for(let i=0; i<numOfItem; i++){
this.listStatus.push({
id: listKeys[i],
name: listKeys[numOfItem+i]
})
}
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"]
只有一句话:
Object.entries(GoalProgressMeasurements).map(([key, value]) => ({id: key, value: value}))
