Install Express

npm install express
npm install cors

Create server.js

const express = require("express");
const cors = require("cors");

const app = express();

app.use(cors());
app.use(express.json());

let users = [
  { id: 1, name: "Alice" },
  { id: 2, name: "Bob" }
];

// Get all users
app.get("/users", (req, res) => res.json(users));

// Get a single user by ID
app.get("/users/:id", (req, res) => {
  const user = users.find(u => u.id === parseInt(req.params.id));
  user ? res.json(user) : res.status(404).json({ error: "User not found" });
});

// Create a new user
app.post("/users", (req, res) => {
  const { name } = req.body;
  if (!name) {
    return res.status(400).json({ error: "Name is required" });
  }
  const newUser = { id: users.length + 1, name };
  users.push(newUser);
  res.status(201).json(newUser);
});

// Update a user by ID
app.put("/users/:id", (req, res) => {
  const user = users.find(u => u.id === parseInt(req.params.id));
  if (!user) {
    return res.status(404).json({ error: "User not found" });
  }
  const { name } = req.body;
  if (!name) {
    return res.status(400).json({ error: "Name is required" });
  }
  user.name = name;
  res.json(user);
});

// Delete a user by ID
app.delete("/users/:id", (req, res) => {
  const userIndex = users.findIndex(u => u.id === parseInt(req.params.id));
  if (userIndex === -1) {
    return res.status(404).json({ error: "User not found" });
  }
  users.splice(userIndex, 1);
  res.json({ message: "User deleted successfully" });
});

app.listen(3000, () => {
  console.log("Server running on port 3000, <http://localhost:3000>")
});