去除Schema自带_id(需要自己设置)

new Schema({ name: String }, { _id: false})

1.document must have an _id before saving

Schema开启了_id:false,而创建Schema实例时没有给值

2.Cast to ObjectId failed for value “0” at path “_id” for model “Item”

没有开启_id:false，默认会生成ObjectId格式的_id，把0赋值给它会出错

3.Invalid $project :: caused by :: Cannot do exclusion on field user_id in inclusion projection

groups = await ModelGroup.aggregate() .match({ user_id: testUserId }) //这里把user_id,设置为0，报错。可能是因为正在使用的原因 //可以直接不设置user_id .project({ user_id:0,id: '$_id', user_id: 0, title: 1, _id: 0 }) .exec();

4.MongoNetworkError: failed to connect to server

mongoose.connect(‘mongodb://root:123456@localhost:27017/todolist’) 失败 账户设置有成了admin的root账户 应该改成todolist的操作账户

5.mongoose 插入数据时多了 __v

创建Schema实例时，添加{ versionKey: false }

const ItemSchema = new mongoose.Schema( { 。。。 }, { versionKey: false } );