如何使用mongoose根据其他字段返回字段

const mongoose = require('mongoose');

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

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

User.findOne({ name: 'John' }, 'name email', function (err, user) {
  if (err) throw err;
  console.log(user);
});

User.findOne({ name: 'John' }, '-age -email', function (err, user) {
  if (err) throw err;
  console.log(user);
});

const fields = { name: 1, email: 1 };

User.findOne({ name: 'John' }, fields, function (err, user) {
  if (err) throw err;
  console.log(user);
});