type MyReadonly2<T, K extends keyof T = keyof T> = {
readonly [Key in K]: T[Key]
} & {
[Key in Exclude<keyof T, K>]: T[Key]
}
/* _____________ 测试用例 _____________ */
import { Alike, Expect } from '@type-challenges/utils'
type cases = [
Expect<Alike<MyReadonly2<Todo1>, Readonly<Todo1>>>,
Expect<Alike<MyReadonly2<Todo1, 'title' | 'description'>, Expected>>,
Expect<Alike<MyReadonly2<Todo2, 'title' | 'description'>, Expected>>,
]
interface Todo1 {
title: string
description?: string
completed: boolean
}
interface Todo2 {
readonly title: string
description?: string
completed: boolean
}
interface Expected {
readonly title: string
readonly description?: string
completed: boolean
}
K extends keyof T = keyof T 中的= keyof T语句有什么作用,我对这个=的用法不太理解,在这里是可以直接用来指定K的类型吗?
这段代码是在这里看到的