Axios响应的React和TypeScript类型？

Question

我试图从API中呈现一个简单的用户列表，该列表返回以下内容：

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

我不完全理解如何使用类型处理Axios响应。TypeScript错误为

类型“｛｝|｛id:number；firstName:string；｝”不可分配给类型“IntrinsicAttributes”

属性“项目”在“{}”类型中缺失，但在“UserListProps”类型中是必需的。

从

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

如果你不希望 Axios 推断值响应的类型为 any，则需要在调用 axios.get 时提供一个类型参数。

并且当您使用 State 创建用户数组时，您传递了一个不正确的类型参数。

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 a type argument
    const [users, setUserList] = useState<TUserList>();

    useEffect(() => {
        // Use [] as a 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;

如果选择导出类型类型TUserList=User[]，则可以在UserList组件中使用它作为道具的类型。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>
                    { /* Do not call the delete function. Just point
                         to it. Set this to null in bind(). */}
                </li>
            ))}
            </ul>
        </Fragment>
    );
};

export default UserList;

Answer 2

axios/index.d.ts中定义了一个通用的get方法

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 );
        });

我认为你把列表传递给子组件的方式是错误的。

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>
    );
};