带有承诺的打字稿索引签名

发布于 2025-01-29 01:19:27 字数 787 浏览 1 评论 0原文

以下课程的正确索引签名是什么？

class MyClass {
  [index: string]: Promise<void> | Promise<MyType>; // not working

  public async methodOne (): Promise<void> { ... }
  public async methodTwo (): Promise<MyType> { ... }
}

我希望能够使用该方法的字符串名称在此类上执行方法：

myClassInstance[stringNameOfMethodOne]()

有两个打字稿错误，一个在方法定义上，一个在方法的使用中。方法定义错误是：

Property 'methodOne' of type '() => Promise<void>' is not assignable to 'string' index type 'Promise<void> | Promise<MyType>'

使用该方法的错误是：

This expression is not callable. No constituent of type 'Promise<MyType> | Promise<void>' is callable.

我已经在JavaScript中完成了此操作，但是对Typescript的索引签名不太熟悉。

原文

What is the correct index signature for the following class?

class MyClass {
  [index: string]: Promise<void> | Promise<MyType>; // not working

  public async methodOne (): Promise<void> { ... }
  public async methodTwo (): Promise<MyType> { ... }
}

I want to be able to execute a method on this class using the string name of the method:

myClassInstance[stringNameOfMethodOne]()

There are two TypeScript errors, one on the method definition and one on the usage of the method. The method definition error is:

Property 'methodOne' of type '() => Promise<void>' is not assignable to 'string' index type 'Promise<void> | Promise<MyType>'

The error on the usage of the method is:

This expression is not callable. No constituent of type 'Promise<MyType> | Promise<void>' is callable.

I've done this in JavaScript but am less familiar with TypeScript's index signatures.

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睫毛溺水了 2025-02-05 01:19:27

您可能只是忘记了功能类型：

class MyClass {
  [index: string]: () => (Promise<void> | Promise<MyType>); // A function type returning a Promise

  public async methodOne (): Promise<void> { ... }
  public async methodTwo (): Promise<MyType> { ... }
}

You probably just forgot the function type:

class MyClass {
  [index: string]: () => (Promise<void> | Promise<MyType>); // A function type returning a Promise

  public async methodOne (): Promise<void> { ... }
  public async methodTwo (): Promise<MyType> { ... }
}

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蔚蓝源自深海 2025-02-05 01:19:27

您可能根本不想要索引签名。因为此功能正常：

interface MyType { myType: true }

class MyClass {
  public async methodOne (): Promise<void> {}
  public async methodTwo (): Promise<MyType> { return { myType: true } }
}

const stringNameOfMethodOne = 'methodOne'
const myClassInstance = new MyClass()
myClassInstance[stringNameOfMethodOne]() // works

String nameofmethodone实际上是字符串字面类型，因此TypeScript确切知道它将查找什么属性，这使所有内容都可以正常工作。

You may not want an index signature at all. Because this works fine:

interface MyType { myType: true }

class MyClass {
  public async methodOne (): Promise<void> {}
  public async methodTwo (): Promise<MyType> { return { myType: true } }
}

const stringNameOfMethodOne = 'methodOne'
const myClassInstance = new MyClass()
myClassInstance[stringNameOfMethodOne]() // works

stringNameOfMethodOne here is actually a string literal type, so typescript knows exactly what property it will look up, which makes everything work.

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