・src/server.js

let users = [
  {
    id: "1",
    name: "Smith",
    age: 55,
    country: "United Kingdom",
    magazines: ["VOGUE-UK", "ELLE"],
  },
  {
    id: "2",
    name: "Michele",
    age: 71,
    country: "United States",
    magazines: ["VOGUE-US", "ELLE"],
  },
  {
    id: "3",
    name: "John",
    age: 43,
    country: "Canada",
    magazines: ["VOGUE-CA", "ELLE"],
  },
];
app.get("/users/:id", (req, res) => {
  const { id } = req.params;
  res.json(users.find((user) => user.id === id));
});

let SERVER_PORT = 8080;
app.listen(SERVER_PORT, () =>
  console.log(`Server is listening on port: ${SERVER_PORT}`)
);

・This file is executed on the server with a command like "node server.js".

・Install Express.js by running a command like "npm install express" if necessary

・If "Server listening on port: 8080" is displayed on the terminal,
means that the server has been successfully connected.

・src/components/user-info.jsx

export const UserInfo = ({ user }) => {
  const { name, age, country, magazines } = user || {};
  return user ? (
    <>
      <h2>{name}</h2>
      <p>Age: {age} years</p>
      <p>Country: {country}</p>
      <h2>Magazines</h2>
      <ul>
        {magazines.map((magazine) => (
          <li key={magazine}> {magazine} </li>
        ))}
      </ul>
    </>
  ) : (
    <h1>Loading...</h1>
  );
};

This component displays name, age, country, and magazines as user information.

・src/components/include-user.jsx

import { useEffect, useState } from "react";
import axios from "axios";

export const includeUser = (Component, userId) => {
  return (props) => {
    const [user, setUser] = useState(null);

    useEffect(() => {
      (async () => {
        const response = await axios.get(`/users/${userId}`);
        setUser(response.data);
      })();
    });

    return <Component {...props} user={user} />;
  };
};

・This component is a High Order Component.

・This component retrieves user information with axios from the server.

・This component returns a component received as props, passing some props and user information as user props.

・src/App.js

import { includeUser } from "./components/include-user";
import { UserInfo } from "./components/user-info";

const UserInfoWithUser = includeUser(UserInfo, "2");

function App() {
  return (
    <>
      <UserInfoWithUser />
    </>
  );
}

export default App;

・This component returns the UserInfoWithUser component witch is High Order Component wrapped by includeUser passing UserInfo and "2" as variables.

React Design Patterns~High Order Components/ Data Loading~