函数签名中通用类型的类型

Question

I am trying to write a generic function where I would like to have an argument of a type of other generic parameter. Here is a code sample:

function find<K,V,P extends keyof V>(map: Map<K,V>, property: P, value: number): boolean {
  for (const entry of Array.from(map.values())) {
    if (entry[property] == value)
      return true;
  }
  return false;
}

let map = new Map<string, string>([["a", "test"]]);
const result: boolean = find<string,string,'length'>(map, 'length', 4); //is the entry 'a' of length 4 ?

This doesn't work since the type of value: number is hard-coded. I would like to be it the type of property:P in the V type. Is this even possible?

Answer 1

使用映射类型

function find<K,V,P extends keyof V>(map: Map<K,V>, property: P, value: V[P])