以下代码可用于在TypeScript中创建enum:

enum e {
    hello = 1,
    world = 2
};

这些值可以通过以下方式访问:

e.hello;
e.world;

我如何创建一个字符串值enum ?

enum e {
    hello = "hello", // error: cannot convert string to e
    world = "world"  // error 
};

当前回答

我也有同样的问题,然后想出了一个很好用的函数:

每个条目的键和值都是字符串,并且相同。 每个条目的值都是从键派生出来的。(即。“不要重复你自己”,不像字符串值的常规枚举) TypeScript类型成熟且正确。(防止拼写错误) 还有一种简单的方法可以让TS自动完成您的选项。(如。打字MyEnum。,并立即看到可用的选项) 还有其他一些优点。(见答案底部)

效用函数:

export function createStringEnum<T extends {[key: string]: 1}>(keysObj: T) {
    const optionsObj = {} as {
        [K in keyof T]: keyof T
        // alternative; gives narrower type for MyEnum.XXX
        //[K in keyof T]: K
    };
    const keys = Object.keys(keysObj) as Array<keyof T>;
    const values = keys; // could also check for string value-overrides on keysObj
    for (const key of keys) {
        optionsObj[key] = key;
    }
    return [optionsObj, values] as const;
}

用法:

// if the "Fruit_values" var isn't useful to you, just omit it
export const [Fruit, Fruit_values] = createStringEnum({
    apple: 1,
    pear: 1,
});
export type Fruit = keyof typeof Fruit; // "apple" | "pear"
//export type Fruit = typeof Fruit_values[number]; // alternative

// correct usage (with correct types)
let fruit1 = Fruit.apple; // fruit1 == "apple"
fruit1 = Fruit.pear; // assigning a new fruit also works
let fruit2 = Fruit_values[0]; // fruit2 == "apple"

// incorrect usage (should error)
let fruit3 = Fruit.tire; // errors
let fruit4: Fruit = "mirror"; // errors

现在有人可能会问,这个“基于字符串的enum”比只使用:

type Fruit = "apple" | "pear";

有几个优点:

Auto-complete is a bit nicer (imo). For example, if you type let fruit = Fruit., Typescript will immediately list the exact set of options available. With string literals, you need to define your type explicitly, eg. let fruit: Fruit = , and then press ctrl+space afterward. (and even that results in unrelated autocomplete options being shown below the valid ones) The TSDoc metadata/description for an option is carried over to the MyEnum.XXX fields! This is useful for providing additional information about the different options. For example: You can access the list of options at runtime (eg. Fruit_values, or manually with Object.values(Fruit)). With the type Fruit = ... approach, there is no built-in way to do this, which cuts off a number of use-cases. (for example, I use the runtime values for constructing json-schemas)

其他回答

//to access the enum with its string value you can convert it to object 
//then you can convert enum to object with proberty 
//for Example :

enum days { "one" =3, "tow", "Three" }

let _days: any = days;

if (_days.one == days.one)
{ 
    alert(_days.one + ' | ' + _days[4]);
}

使用typescript@next中提供的自定义转换器(https://github.com/Microsoft/TypeScript/pull/13940),您可以从字符串字面类型创建字符串值的枚举对象。

请查看我的npm包,ts-transformer-enumerate。

使用示例:

// The signature of `enumerate` here is `function enumerate<T extends string>(): { [K in T]: K };`
import { enumerate } from 'ts-transformer-enumerate';

type Colors = 'green' | 'yellow' | 'red';
const Colors = enumerate<Colors>();

console.log(Colors.green); // 'green'
console.log(Colors.yellow); // 'yellow'
console.log(Colors.red); // 'red'

我正在寻找一种方法来实现typescript枚举中的描述(v2.5),这种模式适合我:

export enum PriceTypes {
    Undefined = 0,
    UndefinedDescription = 'Undefined' as any,
    UserEntered = 1,
    UserEnteredDescription = 'User Entered' as any,
    GeneratedFromTrade = 2,
    GeneratedFromTradeDescription = 'Generated From Trade' as any,
    GeneratedFromFreeze = 3,
    GeneratedFromFreezeDescription = 'Generated Rom Freeze' as any
}

...

    GetDescription(e: any, id: number): string {
        return e[e[id].toString() + "Description"];
    }
    getPriceTypeDescription(price: IPricePoint): string {
        return this.GetDescription(PriceTypes, price.priceType);
    }

打印稿0.9.0.1

enum e{
    hello = 1,
    somestr = 'world'
};

alert(e[1] + ' ' + e.somestr);

打印稿操场

@basarat的回答很棒。下面是一个你可以使用的简化但有点扩展的例子:

export type TMyEnumType = 'value1'|'value2';

export class MyEnumType {
    static VALUE1: TMyEnumType = 'value1';
    static VALUE2: TMyEnumType = 'value2';
}

console.log(MyEnumType.VALUE1); // 'value1'

const variable = MyEnumType.VALUE2; // it has the string value 'value2'

switch (variable) {
    case MyEnumType.VALUE1:
        // code...

    case MyEnumType.VALUE2:
        // code...
}