Mongoose 使用 $in 查找数组

使用 Mongoose 的 $in 运算符可以在查询中查找包含在指定数组中的值的文档。这对于需要查询多个值的情况非常有用，而不必为每个值编写单独的查询。

javascript
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

javascript
const userSchema = new mongoose.Schema({
  name: String,
  hobbies: [String]
});

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

javascript
const hobbiesToSearch = ['音乐', '电影'];
User.find({ hobbies: { $in: hobbiesToSearch } }, (err, users) => {
  if (err) {
    console.error(err);
  } else {
    console.log(users);
  }
});

javascript
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

javascript
const bookSchema = new mongoose.Schema({
  title: String,
  categories: [String]
});

javascript
const Book = mongoose.model('Book', bookSchema);

javascript
const categoriesToSearch = ['科幻', '悬疑'];
Book.find({ categories: { $in: categoriesToSearch } }, (err, books) => {
  if (err) {
    console.error(err);
  } else {
    console.log(books);
  }
});