# TypeScript: 解決 Type 'unknown' is not assignable to type 'never'.ts(2322) 的問題

interface Profile {
  name: string,
  age: number
}

const profile: Profile = { name: 'abc', age: 18 }

// Wrong
function setValueWrong (key: keyof Profile, value: any) {
  const foo = profile[key] // `foo` is typed here
  profile[key] = value  // but why is it `never`
}

// Correct
function setValue <Key extends keyof Profile>(key: Key, value: Profile[Key]) {
  profile[key] = value 
}