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
我使用
Object.entries(GoalProgressMeasurement).filter(e => !isNaN(e[0]as any)).map(e => ({ name: e[1], id: e[0] }));
一条简单的线就可以做到这一点。
它只需要3个简单的步骤 -使用Object.entries加载键和值的组合。 -过滤掉非数字(因为typescript会为反向查找生成值)。 -然后我们将它映射到我们喜欢的数组对象。
其他回答
class EnumHelpers {
static getNamesAndValues<T extends number>(e: any) {
return EnumHelpers.getNames(e).map(n => ({ name: n, value: e[n] as T }));
}
static getNames(e: any) {
return EnumHelpers.getObjValues(e).filter(v => typeof v === 'string') as string[];
}
static getValues<T extends number>(e: any) {
return EnumHelpers.getObjValues(e).filter(v => typeof v === 'number') as T[];
}
static getSelectList<T extends number, U>(e: any, stringConverter: (arg: U) => string) {
const selectList = new Map<T, string>();
this.getValues(e).forEach(val => selectList.set(val as T, stringConverter(val as unknown as U)));
return selectList;
}
static getSelectListAsArray<T extends number, U>(e: any, stringConverter: (arg: U) => string) {
return Array.from(this.getSelectList(e, stringConverter), value => ({ value: value[0] as T, presentation: value[1] }));
}
private static getObjValues(e: any): (number | string)[] {
return Object.keys(e).map(k => e[k]);
}
}
我已经解出来了。 假设您有一个如下所示的枚举
export enum UnitEnum {
GRAM = 'gm',
KILOGRAM = 'kg',
LITRE = 'lt',
CENTIMETER = 'cm',
INCH = 'in',
METER = 'mt',
KILOMETER = 'km',
}
你有这样一门课，
export interface Unit {
Name: string;
Symbol: string;
}
然后，您可以创建一个如下所示的函数，将异构枚举映射到某个类型的对象，
export function getDefaultUnits() {
const myUnits = Object.entries(UnitEnum).map(x => {
return { Name: x[0], Symbol: x[1] } as Unit
})
console.log(myUnits);
return myUnits;
}
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]
);
}
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"]
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]);
}
