我想迭代一个TypeScript枚举对象,并获得每个枚举符号名称,例如: enum myEnum {entry1, entry2}
for (var entry in myEnum) {
// use entry's name here, e.g., "entry1"
}
我想迭代一个TypeScript枚举对象,并获得每个枚举符号名称,例如: enum myEnum {entry1, entry2}
for (var entry in myEnum) {
// use entry's name here, e.g., "entry1"
}
当前回答
这里发现的另一个有趣的解决方案是使用ES6 Map:
export enum Type {
low,
mid,
high
}
export const TypeLabel = new Map<number, string>([
[Type.low, 'Low Season'],
[Type.mid, 'Mid Season'],
[Type.high, 'High Season']
]);
USE
console.log(TypeLabel.get(Type.low)); // Low Season
TypeLabel.forEach((label, value) => {
console.log(label, value);
});
// Low Season 0
// Mid Season 1
// High Season 2
其他回答
如果你只搜索名称,然后迭代使用:
Object.keys(myEnum).map(key => myEnum[key]).filter(value => typeof value === 'string') as string[];
根据TypeScript文档,我们可以通过Enum和静态函数来实现这一点。
使用静态函数获取Enum名称
enum myEnum {
entry1,
entry2
}
namespace myEnum {
export function GetmyEnumName(m: myEnum) {
return myEnum[m];
}
}
now we can call it like below
myEnum.GetmyEnumName(myEnum.entry1);
// result entry1
要阅读更多关于Enum的静态函数,请点击下面的链接 https://basarat.gitbooks.io/typescript/docs/enums.html
这对于基于键值的enum更有效:
enum yourEnum {
["First Key"] = "firstWordValue",
["Second Key"] = "secondWordValue"
}
Object.keys(yourEnum)[Object.values(yourEnum).findIndex(x => x === yourValue)]
// Result for passing values as yourValue
// FirstKey
// SecondKey
使用当前版本的TypeScript,你可以使用这些函数将Enum映射到你选择的记录。注意,不能用这些函数定义字符串值,因为它们查找值为数字的键。
enum STATES {
LOGIN,
LOGOUT,
}
export const enumToRecordWithKeys = <E extends any>(enumeration: E): E => (
Object.keys(enumeration)
.filter(key => typeof enumeration[key] === 'number')
.reduce((record, key) => ({...record, [key]: key }), {}) as E
);
export const enumToRecordWithValues = <E extends any>(enumeration: E): E => (
Object.keys(enumeration)
.filter(key => typeof enumeration[key] === 'number')
.reduce((record, key) => ({...record, [key]: enumeration[key] }), {}) as E
);
const states = enumToRecordWithKeys(STATES)
const statesWithIndex = enumToRecordWithValues(STATES)
console.log(JSON.stringify({
STATES,
states,
statesWithIndex,
}, null ,2));
// Console output:
{
"STATES": {
"0": "LOGIN",
"1": "LOGOUT",
"LOGIN": 0,
"LOGOUT": 1
},
"states": {
"LOGIN": "LOGIN",
"LOGOUT": "LOGOUT"
},
"statesWithIndex": {
"LOGIN": 0,
"LOGOUT": 1
}
}
基于上面的一些回答,我提出了这个类型安全的函数签名:
export function getStringValuesFromEnum<T>(myEnum: T): (keyof T)[] {
return Object.keys(myEnum).filter(k => typeof (myEnum as any)[k] === 'number') as any;
}
用法:
enum myEnum { entry1, entry2 };
const stringVals = getStringValuesFromEnum(myEnum);
stringVals的类型是'entry1' | 'entry2'
看看它的实际应用