城市X选与 2+1 拼购模式：循环社交裂变，促进用户增长

bash复制代码npm install express mongoose body-parser

javascript复制代码const express = require('express');  const mongoose = require('mongoose');  const bodyParser = require('body-parser');    const app = express();  const port = 3000;    // 连接MongoDB数据库  mongoose.connect('mongodb://localhost/citycoolselect', { useNewUrlParser: true, useUnifiedTopology: true });    // 用户模型  const userSchema = new mongoose.Schema({    name: String,    email: String,    password: String, // 注意：实际中应使用加密存储密码    referralCode: String, // 邀请码    referrals: [{ type: mongoose.Schema.Types.ObjectId, ref: 'User' }], // 邀请的人    orders: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Order' }], // 订单    // 其他用户属性...  });    // 订单模型  const orderSchema = new mongoose.Schema({    userId: { type: mongoose.Schema.Types.ObjectId, ref: 'User' },    products: [{ name: String, price: Number, quantity: Number }], // 产品列表    totalAmount: Number, // 总金额    isFree: Boolean, // 是否免单    // 其他订单属性...  });    const User = mongoose.model('User', userSchema);  const Order = mongoose.model('Order', orderSchema);    // 中间件  app.use(bodyParser.json());    // 路由示例  app.post('/register', async (req, res) => {    const { name, email, password } = req.body;    const user = new User({ name, email, password, referralCode: generateReferralCode() }); // 生成邀请码    await user.save();    res.status(201).send({ message: 'User registered successfully', user });  });    app.post('/login', async (req, res) => {    const { email, password } = req.body;    const user = await User.findOne({ email, password }); // 注意：实际中应验证密码    if (user) {      res.status(200).send({ message: 'Login successful', user });    } else {      res.status(401).send({ message: 'Invalid credentials' });    }  });    app.post('/order', async (req, res) => {    const { userId, products } = req.body;    const totalAmount = products.reduce((sum, product) => sum + product.price * product.quantity, 0);    const order = new Order({ userId, products, totalAmount, isFree: false }); // 初始设为非免单    // 这里可以添加排队免单逻辑    await order.save();    // 添加订单到用户    await User.findByIdAndUpdate(userId, { $push: { orders: order._id } });    res.status(201).send({ message: 'Order placed successfully', order });  });    // 示例函数：生成邀请码  function generateReferralCode() {    return Math.random().toString(36).substr(2, 9);  }    app.listen(port, () => {    console.log(`Server running at http://localhost:${port}`);  });

jsx复制代码import React, { useState, useEffect } from 'react';  import axios from 'axios';    const App = () => {    const [user, setUser] = useState(null);    const [orders, setOrders] = useState([]);      useEffect(() => {      // 可以在这里添加登录状态检查或自动登录逻辑    }, []);      const register = async (name, email, password) => {      try {        const response = await axios.post('/register', { name, email, password });        setUser(response.data.user);      } catch (error) {        console.error('Registration error:', error);      }    };      const login = async (email, password) => {      try {        const response = await axios.post('/login', { email, password });        setUser(response.data.user);      } catch (error) {        console.error('Login error:', error);      }    };      const placeOrder = async (products) => {      try {        const response = await axios.post('/order', { userId: user._id, products });        setOrders([...orders, response.data.order]);      } catch (error) {        console.error('Order error:', error);      }    };      return (      <div>        {!user ? (          <div>            <h1>Register</h1>            <input type="text" placeholder="Name" />            <input type="email" placeholder="Email" />            <input type="password" placeholder="Password" />            <button onClick={(e) => register(e.target.elements[0].value, e.target.elements[1].value, e.target.elements[2].value)}>Register</button>              <h1>Login</h1>            <input type="email" placeholder="Email" />            <input type="password" placeholder="Password" />            <button onClick={(e) => login(e.target.elements[0].value, e.target.elements[1].value)}>Login</button>          </div>        ) : (          <div>            <h1>Welcome, {user.name}!</h1>            <button onClick={() => placeOrder([{ name: 'Product 1', price: 10, quantity: 1 }])}>Place Order</button>            <h2>Your Orders</h2>            <ul>              {orders.map((order) => (                <li key={order._id}>{order.totalAmount}</li>              ))}            </ul>          </div>        )}      </div>    );  };    export default App;