Mongoose - save after lean - mongodb

Question

I'm fetching an object from mongo using mongoose but i want to use lean as there are attributes that aren't in mongoose model (strict:false)
After modifying that object i can't save it back
let order = await Order.findOne({_id: req.body.id}).populate({path: 'o_s', match: {removed: false}}).lean()
order.save() //not working as it's not mongoose model any more
Order.update({_id:order._id},{order}).exec(function(){
return res.json({status: true, message: 'Order Updated', order: order});
}) //not giving error but not updating too
any suggestions ?

Answer 1

In order to update the doc you retrieved from the db, you have to remove the _id property.
Consider this contrived example:
#!/usr/bin/env node
'use strict';
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');
const conn = mongoose.connection;
const Schema = mongoose.Schema;
const schema = new Schema({
name: String
});
schema.set('strict', false);
const Test = mongoose.model('test', schema);
const test = new Test({
name: 'Henry',
nick: 'Billy'
});
async function run() {
await conn.dropDatabase();
await test.save();
let doc = await Test.findOne({}).lean();
const id = doc._id;
delete doc._id;
doc.name = 'Billy';
doc.nick = 'The Kid';
await Test.update({ _id: id }, doc);
let updated = await Test.findOne({});
console.log(updated);
return conn.close();
}
run();
output:
{ _id: 5ad34679bc95f172c26f3382,
name: 'Billy',
nick: 'The Kid',
__v: 0 }
note that you lose auto versioning in this scenario, if this is important to you, you'll need to manually increment the version property.

Answer 2

i suggest to doesn't use lean() because it has some performance isues that i realized.
otherwise you can use JSON.parse(JSON.stringify(order)) and for some reasean it's a better approach. especially wen you want to iterate over the result ( in my case it was two times faster for iteration).