Can't instance a model from mongoose after update from v4 to v6

I’m submitting a…

[ ] Regression 
[x] Bug report
[ ] Feature request
[ ] Documentation issue or request
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Duplicated issue https://github.com/nestjs/nest/issues/2585 but I was not sure where should I actually report this bug, so, I am also opening it here

Current behavior

I was using v4 of nestjs and i was instancing new mongoose model with

import { model } from 'mongoose';

const someModel: Model = model(modelName, someSchema)

After upgrading nest to v6, this is not working anymore. I switched to officially suggested way of using it with @InjectModel(), but there is still a case where I have to instance model like this. I want to write a prehook in which I want to do some query on some model. But when I do it like this, it can’t execute a query, and it does not throw an error. But it stops execution of code.

My assumption is that somehow, mongoose.connection is not set globally, so, model does not know through which connection to execute query.

Expected behavior

Expecting that using mongoose.model() still can execute query, or if it is possible somehow to extract connection from app.module

Minimal reproduction of the problem with instructions

import { model } from 'mongoose';

Schema.pre('save', function (next: Function): void {
   const someModel: Model = model(modelName, schema);
   someModel.countDocuments(query).then((result: number) => {
       return next(true);
   }).catch((error) => next(error));
});

Some example code, which should be executed, not providing full example, I think it is not necessary. I can’t use this https://docs.nestjs.com/recipes/mongodb, because I don’t need this feature in some provider or module, so no option to inject it

What is the motivation / use case for changing the behavior?

Environment

Nest version: 6.4.0

 
For Tooling issues:
- Node version: 8.13 
- Platform: Linux, docker 

Others:

- Mongoose: 5.6.3

[igorivaniuk]

@NenadJovicic for now i doing something like this

export const getModel = name => {
  return mongoose.connections[1].model(name)
}

Schema.pre('save', function (next: Function): void {
   const someModel = getModel(modelName);
   someModel.countDocuments(query).then((result: number) => {
       return next(true);
   }).catch((error) => next(error));
});

[jmcdo29]

const someModel = mongoose.model(EventModel.name, EventSchema); TypeError: Cannot read property ‘model’ of undefined

If I had to bet, it has to deal with how you import mongoose. Try a named import like import * as mongoose from 'mongoose' For further support please use our Discord channel (Support). We are using GitHub to track Bug Reports, Feature Requests, and Regressions.