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TypeScript 动态参数和返回类型


我正在开发一个 Angular 应用程序,该应用程序必须与一个具有某些安全限制的后端进行通信,这些限制我在每次调用时都必须处理。为了方便处理这些调用,我创建了一个像这样的封装方法:

type ApiResponse<T = any> = {
  status: number,
  data: T,
  error?: string
}

type ApiCall<T=any> = (...args: any[]) => ApiResponse<T>;

const makeApiCall = <T extends ApiCall>(apiCall: T, ...params: Parameters<T>): ReturnType<T> => {
  // Execute the "apiCall" method with the parameters, deal with restrictions, parse the response etc
}

所以,假设我有两个 API 调用(它们可以有任意数量的参数和类型):

const f1: ApiCall<string> = (a: number, b: string) => {
  // Do logic
  return {
    status: 200,
    data: "Data sample"
  }
}

const f2: ApiCall<string[]> = (a: string, b: string, c: number, d: number) => {
  // Do logic
  return {
    status: 200,
    data: [ a, b ]
  }
}

我可以使用封装器来运行它们:

makeApiCall(f1, 2, 4);

makeApiCall(f2, "String", "Another", 10, 20);

然而,没有什么能阻止我发送错误的参数数量或类型,例如:

makeApiCall(f1, 2, 4, "WRONG PARAMETER");

makeApiCall(f2, "Wrong number and type of params", 10, true);

是否有可能在上述定义中实现类型安全,以便 Typescript 编译器在使用包装器时显示提示和错误?

提前谢谢,

答案#1

尽量避免声明显式的泛型参数。TS 应该推断所有类型。让它来做繁重的工作 :)

type ApiResponse<T> = {
    status: number,
    data: T,
    error?: string
}

type Fn = (...args: any[]) => any

const makeApiCall = <
    F extends Fn
>(apiCall: F, ...params: Parameters<F>): ReturnType<F> =>
    apiCall(...params)

const f1 = (a: number, b: string) => {
    // Do logic
    return {
        status: 200,
        data: [a, b]
    }
}

const f2 = (a: string, b: string, c: number, d: number) => {
    // Do logic
    return {
        status: 200,
        data: [a, b]
    }
}

/**
 * Ok
 */
// Return -> {  status: number;  data: (string|number)[];  }
const result1 = makeApiCall(f1, 42, 'str');

// Return -> {  status: number;  data: string[];  }
const result2 = makeApiCall(f2, "String", "Another", 10, 20);


/**
 * Errors
 */
makeApiCall(f1, 2, 4); // expected error


makeApiCall(f1, 2, 4, "WRONG PARAMETER"); // expected error

makeApiCall(f2, "Wrong number and type of params", 10, true); // expected error

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