我可以定义一个具有“可覆盖”返回类型的泛型函数吗？

Question

我想要这样的东西：

type httpRequestHandler = <Payload>(request: RequestData) => Payload

const httpRouteA: httpRequestHandler = (request) => {
    return 'Test'
}

const httpRouteB: httpRequestHandler = (request) => {
    return 13
}

编译器可以在这里推断string和number而不让我做类似httpRequestHandler<string>和httpRequestHandler<number>吗？

type PayloadA = ReturnType<typeof httpEndpointA> // string
type PayloadB = ReturnType<typeof httpEndpointB> // number

Answer 1

我设法让它像这样工作：

const httpRouteA = (request: RequestData) => {
    return 'Test'
}

type PayloadA = ReturnType<typeof httpEndpointA> // string.

const httpRouteB = (request: RequestData) => {
    return 13
}

type PayloadB = ReturnType<typeof httpEndpointB> // number.

这是一种权衡，因为我每次都必须键入函数参数，但编译器在这里正确推断了返回类型。