Mutable
约 184 字小于 1 分钟
2022-12-01
题目
Github: Mutable
实现一个通用的类型 Mutable<T> ，使类型 T 的全部属性可变（非只读）。
interface Todo {
readonly title: string
readonly description: string
readonly completed: boolean
}
type MutableTodo = Mutable<Todo>
// { title: string; description: string; completed: boolean; }解题思路
略。
答案
type Mutable<T extends object> = {
-readonly [P in keyof T]: T[P]
}验证
interface Todo1 {
title: string
description: string
completed: boolean
meta: {
author: string
}
}
type List = [1, 2, 3]
type cases = [
Expect<Equal<Mutable<Readonly<Todo1>>, Todo1>>,
Expect<Equal<Mutable<Readonly<List>>, List>>,
]
type errors = [
// @ts-expect-error
Mutable<'string'>,
// @ts-expect-error
Mutable<0>,
]