[英]FlowType : return type of function (k) => obj[k]
I have a User
object:我有一个
User
对象:
type User = {
name: string,
};
That has a get()
function, that takes in parameter the key of an attribute on User
and returns this attribute.它有一个
get()
函数,它在参数中接受User
属性的键并返回该属性。 The function get is函数get是
User.prototype.get = (prop) => {
return this[prop];
};
How can I write this fonction definition ?我该如何编写这个函数定义? Here's what I got so far:
这是我到目前为止所得到的:
type User = {
name: string,
get: (k: $Keys<User>) => any, // How can I change any to the correct property type ?
};
Seems like you can use now $ElementType<T, K>
.似乎您现在可以使用
$ElementType<T, K>
。 To be confirmed !待确认!
Source: https://github.com/facebook/flow/issues/4122#issuecomment-314700605来源: https : //github.com/facebook/flow/issues/4122#issuecomment-314700605
EDIT: Working example编辑: 工作示例
/* @flow */
type User = {
name: string,
age: number,
}
const user: User = {
name: 'Ilyes',
age: 21,
}
function get<K: string>(key: K): $ElementType<User, K> {
return user[key];
}
const number: number = get('name'); // error
const number2: number = get('age'); // works
const string: string = get('name'); // works
const string2: string = get('age'); // error
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.