如何在Node.js应用中处理mongoose中的错误

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('MongoDB connected');
  })
  .catch((err) => {
    console.error('MongoDB connection error:', err);
  });

const userSchema = new mongoose.Schema({
  name: String,
  age: Number,
  email: String
});

const User = mongoose.model('User', userSchema);

try {
  const newUser = new User({
    name: 'John',
    age: 25,
    email: 'john@example.com'
  });

  await newUser.save();
  console.log('User saved successfully');
} catch (err) {
  console.error('Error saving user:', err);
}

const newUser = new User({
  name: 'John',
  age: 25,
  email: 'john@example.com'
});

newUser.save()
  .then(() => {
    console.log('User saved successfully');
  })
  .catch((err) => {
    console.error('Error saving user:', err);
  });