React 和 Typescript，Axios 响应的类型有哪些？

Question

我正在尝试从返回以下内容的 API 中呈现一个简单的用户列表：

[{"UserID":2,"FirstName":"User2"},{"UserID":1,"FirstName":"User1"}]

我不完全了解如何处理带有类型的 Axios 响应。打字稿错误是

Type '{} | { id: number; firstName: string; }' is not assignable to type 'IntrinsicAttributes & UserListProps & { children?: ReactNode; }'.
Property 'items' is missing in type '{}' but required in type 'UserListProps'.

来自下面Users.tsx 文件中的<UserList /> 元素。我的User接口错了吗？

import React, {useEffect, useState, Fragment } from 'react';
import UserList from './UserList';
import axios, {AxiosResponse} from 'axios';

interface User {
    id: number;
    firstName: string;
}

const Users: React.FC = (props) => {
    const [users, setUserList] = useState<User>();

    useEffect(() => {
        // Use [] as second argument in useEffect for not rendering each time
        axios.get('http://localhost:8080/admin/users')
        .then((response: AxiosResponse) => {
            console.log(response.data);
            setUserList( response.data );
        });
    }, []);

    return (
        <Fragment>
            <UserList {...users} />
        </Fragment>

    );
};
export default Users;

下面是我的UserList.tsx。

import React, {Fragment } from 'react';

interface UserListProps {
    items: {id: number, firstName: string}[];
};

const UserList: React.FC<UserListProps> = (props) => {
    return (
        <Fragment>
            <ul>
            {props.items.map(user => (
                <li key={user.id}>
                    <span>{user.firstName}</span>
                    {/* not call delete function, just point to it
                    // set this to null in bind() */}
                </li>
            ))}
            </ul>
        </Fragment>
    );
};

export default UserList;

Answer 1

有generic get method defined in axios/index.d.ts

get<T = never, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig<T>): Promise<R>;

例子

interface User {
    id: number;
    firstName: string;
}


axios.get<User[]>('http://localhost:8080/admin/users')
        .then(response => {
            console.log(response.data);
            setUserList( response.data );
        });

--编辑

我认为您将列表以错误的方式传递给子组件。

const [users, setUserList] = useState<User[]>([]);

<UserList items={users} />

interface UserListProps {
    items: User[];
};

const UserList: React.FC<UserListProps> = ({items}) => {
    return (
        <Fragment>
            <ul>
            {items.map(user => (
                <li key={user.id}>
                    <span>{user.firstName}</span>
                </li>
            ))}
            </ul>
        </Fragment>
    );
};

Answer 2

如果您不希望 axios 推断值 response 的类型，则需要在调用 axios.get 时提供类型参数。

当您useState 创建用户数组时，您传递的类型参数不正确。

正确的方法

interface User {
  id: number;
  firstName: string;
}

// initialized as an empty array
const [users, setUserList] = useState<User[]>([]); // users will be an array of users

例如，

import React, {useEffect, useState, Fragment } from 'react';
import UserList from './UserList';
import axios from 'axios';

interface User {
  id: number;
  firstName: string;
}

// you can export the type TUserList to use as -
// props type in your `UserList` component
export type TUserList = User[]

const Users: React.FC = (props) => {
   // you can also use User[] as type argument
    const [users, setUserList] = useState<TUserList>();

    useEffect(() => {
        // Use [] as second argument in useEffect for not rendering each time
        axios.get<TUserList>('http://localhost:8080/admin/users')
        .then((response) => {
            console.log(response.data);
            setUserList( response.data );
        });
    }, []);

    return (
        <Fragment>
            <UserList {...users} />
        </Fragment>

    );
};
export default Users;

如果您选择导出类型type TUserList = User[]，您可以在UserList 组件中使用它作为道具类型。例如，

import React, {Fragment } from 'react';
import { TUserList } from './Users';

interface UserListProps {
    items: TUserList // don't have to redeclare the object again
};

const UserList: React.FC<UserListProps> = (props) => {
    return (
        <Fragment>
            <ul>
            {props.items.map(user => (
                <li key={user.id}>
                    <span>{user.firstName}</span>
                    {/* not call delete function, just point to it
                    // set this to null in bind() */}
                </li>
            ))}
            </ul>
        </Fragment>
    );
};

export default UserList;