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
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
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]);
}
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;
}
简单的解决方案。您可以使用以下函数将Enum转换为对象数组。
buildGoalProgressMeasurementsArray(): Object[] {
return Object.keys(GoalProgressMeasurements)
.map(key => ({ id: GoalProgressMeasurements[key], name: key }))
}
如果你需要去掉下划线，我们可以像下面这样使用regex:
buildGoalProgressMeasurementsArray(): Object[] {
return Object.keys(GoalProgressMeasurements)
.map(key => ({ id: GoalProgressMeasurements[key], name: key.replace(/_/g, ' ') }))
}
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,
};
});
