打字稿解包重载函数的参数

Question

为了说明我所说的“解包”的意思，请考虑以下示例

function simpleFunc(a: number, b: string): void { /* ... */ }
function simpleProxy(args: [number, string]) {
    simpleFunc(...args)
}

这很好用，typescript 将 [number, string] 映射到 (a: number, b: string)。我有一个用例，我必须对具有重载签名的更复杂的函数执行类似的操作，如下所示：

function overloadFunc(name: string): void
function overloadFunc(name: string, content: number): void
function overloadFunc(content: number): void
function overloadFunc(name_or_content: string | number, maybe_content?: number): void {
    /* ... */
}

现在无法解包编译。我试过这个：

function overloadProxy1(args: [string] | [string, number] | [number]) {
    overloadFunc(...args);
    //           ^^^^^^^
    // Expected 1-2 arguments, but got 0 or more.(2556)
    // ... An argument for 'name' was not provided.
}

还有这个：

function overloadProxy2(args: [string | number, number?]) {
    overloadFunc(...args);
    //           ^^^^^^^
    // Argument of type 'string | number' is not assignable to parameter of type 'string'.
    // Type 'number' is not assignable to type 'string'.(2345)
}

有没有办法让它工作？如果没有，这是否记录在某处？

Answer 1

答案是这个可爱的 Parameters 类型实用程序：


// This way if you want to call it like overloadProxy1(['name'])
function overloadProxy1(args: Parameters<typeof overloadFunc>) {
  // ...
}

// Or this way if you want to call it like overloadProxy1('name')
function overloadProxy1(...args: Parameters<typeof overloadFunc>) {
  // ...
}

Link to TypeScript playground

Link to documentation

打字稿解包重载函数的参数

Typescript unpacking arguments to overloaded function

overloading

argument-unpacking

typescript