创建新字段不希望将mongoose.Types.ObjectId保存为MongoDB中的列

可以使用mongoose.Schema.Types.Mixed来代替mongoose.Types.ObjectId，这样可以将任何类型的数据存储到该字段的值中。以下是示例代码：

const userSchema = new mongoose.Schema({ firstName: String, lastName: String, friends: [mongoose.Schema.Types.Mixed] });

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

const user1 = new User({ firstName: 'John', lastName: 'Doe', friends: [ {name: 'Jane', _id: new mongoose.Types.ObjectId()}, {name: 'Bob', _id: new mongoose.Types.ObjectId()} ] });

user1.save();