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]
})
}
其他回答
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"}]
只有一句话:
Object.entries(GoalProgressMeasurements).map(([key, value]) => ({id: key, value: value}))
我不喜欢上面的答案，因为它们都不能正确地处理字符串/数字的混合，可以在TypeScript enum中作为值。
下面的函数遵循TypeScript枚举的语义，给出键到值的正确映射。从那里，获取一个对象数组或者仅仅是键或者仅仅是值是很简单的。
/**
* Converts the given enum to a map of the keys to the values.
* @param enumeration The enum to convert to a map.
*/
function enumToMap(enumeration: any): Map<string, string | number> {
const map = new Map<string, string | number>();
for (let key in enumeration) {
//TypeScript does not allow enum keys to be numeric
if (!isNaN(Number(key))) continue;
const val = enumeration[key] as string | number;
//TypeScript does not allow enum value to be null or undefined
if (val !== undefined && val !== null)
map.set(key, val);
}
return map;
}
使用示例:
enum Dog {
Rover = 1,
Lassie = "Collie",
Fido = 3,
Cody = "Mutt",
}
let map = enumToMap(Dog); //Map of keys to values
let objs = Array.from(map.entries()).map(m => ({id: m[1], name: m[0]})); //Objects as asked for in OP
let entries = Array.from(map.entries()); //Array of each entry
let keys = Array.from(map.keys()); //An array of keys
let values = Array.from(map.values()); //An array of values
我还要指出OP是逆向思考枚举的。枚举中的“键”在技术上是在左边，而值在右边。TypeScript允许你尽可能多地重复RHS上的值。
this worked for me :
export enum FeedBackType {
FEEDBACK1= 'FEEDBACK1',
FEEDBACK2= 'FEEDBACK2',
FEEDBACK3= 'FEEDBACK3',
}
-----------------------------------------------------------------
export function getTypeFeedBackList() {
let feedbackList: FeedBackType[] = [];
Object.keys(FeedBackType).map((key) => {
let strEnum = key as unknown as FeedBackType;
feedbackList.push(strEnum);
});
return feedbackList;
}
----------------------------------------------------------------
declare this :
public feedbackList: FeedBackType[] = [];
and after call your function in :
ngOnInit(): void {
this.feedbackList = getTypeFeedBackList();
console.log(this.feedbackList);
}
Happy coding ;)
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",
}
