Mongoose Error: Cannot read property 'length' of undefined in NestJs

Question

I am using nests framework and versions of mongodb and mongoose are as specified below. Please refer to the screenshot for error in detail.

versions

"mongodb": "4.0.0",
"mongoose": "5.5.12",

Error Screenshot

User Document Module

import { Module } from '@nestjs/common';
import { UserDocumentsService } from './user-documents.service';
import { UserDocumentsController } from './user-documents.controller';
import { MongooseModule } from '@nestjs/mongoose';
import { UserDocumentsSchema } from './schema/user-documents.schema';

@Module({
    imports: [
        // showing error on this line
        MongooseModule.forFeature([
            { name: 'UserDocument', schema: UserDocumentsSchema },
        ]),
    ],
    controllers: [UserDocumentsController],
    providers: [UserDocumentsService],
})
export class UserDocumentsModule {}

App.module.ts

@Module({
imports: [
        MongooseModule.forRootAsync({
            imports: [SharedModule],
            useFactory: async (configService: ConfigService) => ({
                uri: configService.mongoDBName(),
                useNewUrlParser: true,
                useFindAndModify: false,
            }),
            inject: [ConfigService],
        }),
        UserDocumentsModule,
    ],
    providers: [AppGateway],
})
export class AppModule implements NestModule {
    configure(consumer: MiddlewareConsumer): MiddlewareConsumer | void {
        consumer.apply(contextMiddleware).forRoutes('*');
    }
}

UPDATE I think there is something wrong with the mongoose imports in the schema file. It says "could not find declaration for module 'mongoose'".

I tried removing and reinstalling mongoose and it's types. But now it shows new error.

I tried solutions mentioned in this post: Node.js heap out of memory

But this also didn't work for me. I'm using Mac-M1 with 8GB config.

UPDATE The issue has been resolved now. The project is running on node v10.24.1 and I was using node v16.6.2. After downgrading node version using NVM, this issue is gone.

Why are you importing the `SharedModule` into the `MongooseModule`? In generell you have to import the `ConfigModule` from `@nestjs/config`. Does this fix your issue? — Lars Flieger, Aug 21 '21 at 23:00
@LarsFlieger the problem still persists even after removing shared module from mongoose imports. I don't think that should be an issue. — Sachin Yadav, Aug 24 '21 at 05:08

score 0 · Answer 1 · answered Aug 23 '21 at 15:25

0

You'll have to pull SharedModule import off MongooseModule.

Try this:

@Module({
    imports: [
        MongooseModule.forRootAsync({
            useFactory: async (configService: ConfigService) => ({
                uri: configService.mongoDBName(),
                useNewUrlParser: true,
                useFindAndModify: false,
            }),
            inject: [ConfigService],
        }),
        UserDocumentsModule,
        SharedModule
    ],
    providers: [AppGateway],
})

export class AppModule implements NestModule {
    configure(consumer: MiddlewareConsumer): MiddlewareConsumer | void {
        consumer.apply(contextMiddleware).forRoutes('*');
    }
}

answered Aug 23 '21 at 15:25

Paulo Fabrício

319
3
17

the problem still persists even after removing shared module from mongoose imports. – Sachin Yadav Aug 24 '21 at 05:08
Try to remove the folder node_modules and run npm install – Paulo Fabrício Aug 25 '21 at 11:28
I did that. But now it shows "Javascript heap out of memory". The same project is running well and good on my other colleagues system. and the setup is exactly the same. I am still digging into the issue and will update as soon as I find something. – Sachin Yadav Aug 26 '21 at 07:17
Did you reinstall node? – Paulo Fabrício Aug 27 '21 at 16:42

score 0 · Accepted Answer · answered Sep 01 '21 at 04:04

0

It was because I was using a wrong version of node. The project was built on node v10.24.1 and I was using node v16.6.2.

After downgrading node version using NVM, I was able to fix this issue.

answered Sep 01 '21 at 04:04

Sachin Yadav

128
3
12

Mongoose Error: Cannot read property 'length' of undefined in NestJs

2 Answers2