React-使用expressrouter和mongoose，哪种方法更好？

无论使用哪种方式，都需要先安装mongoose和express模块。

1. 使用mongoose.connect()连接数据库进行查询，并使用express中的router功能：

// server.js

const express = require('express');
const router = require('./routes/api');
const mongoose = require('mongoose');
const app = express();

// DB Config
const db = require('./config/keys').mongoURI;

// Connect to MongoDB
mongoose
  .connect(db, { useNewUrlParser: true })
  .then(() => console.log('MongoDB connected...'))
  .catch(err => console.log(err));

// Use Routes
app.use('/api', router);

const port = process.env.PORT || 5000;

app.listen(port, () => console.log(`Server started on port ${port}`));

// routes/api.js

const express = require('express');
const router = express.Router();
const Item = require('../models/Item');

// @route   GET api/items
// @desc    Get All Items
// @access  Public
router.get('/items', (req, res) => {
  Item.find()
    .then(items => res.json(items))
    .catch(err => console.log(err));
});

module.exports = router;

2. 使用mongoose自带的路由功能进行查询，不需要使用额外的express路由：

// server.js

const express = require('express');
const mongoose = require('mongoose');
const app = express();
const Item = require('./models/Item');

// DB Config
const db = require('./config/keys').mongoURI;

// Connect to MongoDB
mongoose
  .connect(db, { useNewUrlParser: true })
  .then(() => console.log('MongoDB connected...'))
  .catch(err => console.log(err));

// Get All Items
app.get('/api/items', (req, res) => {
  Item.find()
    .then(items => res.json(items))
    .catch(err => console.log(err));
});

const port = process.env.PORT || 5000;

app.listen(port, () => console.log(`Server started on port ${port}`));

无论使用哪种方式，需要在models文件夹中创建对应的数据模型：

// models/Item.js