curried 定义在 uncurried 定义之后时出现 Typescript 错误

Question

我收到错误消息：Expected 1 arguments, but got 2.ts(2554) 当我将方法的未柯里化定义放在柯里化定义之上时。

未通过 dtslint 测试：

function match(regExpression: RegExp, str: string): string[]; 
function match(regExpression: RegExp): (str: string) => string[]; 

function throttle<T, U>(fn: (input: T) => U, ms: number): (input: T) => U;
function throttle<T, Q, U>(
  fn: (input1: T, input2: Q) => U, ms: number
): (input1: T, input2: Q) => U;

it('match', () => {
    const fn = throttle(match, 1000)
    fn(/foo/,'foo bar')  // line of error
})

如果我将柯里化 match 定义移动到非柯里化定义上方，则错误消失。

我的问题是我真的应该将未柯里化版本放在柯里化版本之后，还是 throttle 定义有误？

问题的上下文是为类似于 ramda 的库编写 Typescript 定义。

Answer 1

Typescript 按从上到下的顺序检查重载的签名（内部交集类型）。当 throttle 选择使用哪个签名来推断泛型参数（几乎与条件类型相同）时，它总是选择最后一个签名。

描述了与 TS 类型系统密切相关的特性 here:

When inferring from a type with multiple call signatures (such as the type of an overloaded function), inferences are made from the last signature (which, presumably, is the most permissive catch-all case). It is not possible to perform overload resolution based on a list of argument types (this would require us to support typeof for arbitrary expressions, as suggested in #6606, or something similar).

curried 定义在 uncurried 定义之后时出现 Typescript 错误

Typescript error when curried defition is after the uncurried definition

typescript

definitelytyped