Using NestJS Axios, a simple http get request throws "Cannot read properties of undefined (reading 'emit')" error

Question

Versions I'm using in my NestJS project (I show just the relevant packages):

• "@nestjs/common": "^9.4.0",
• "@nestjs/axios": "^2.0.0",
• "axios": "^1.3.6",
• "follow-redirects": "^1.15.2",

I've tried to follow the documentation here from the beginning: https://docs.nestjs.com/techniques/http-module

I've created a module called geo.module.ts, which looks like this:

import { Module } from '@nestjs/common';
import { GeoService } from './geo.service';
import { GeoController } from './geo.controller';
import { HttpModule } from '@nestjs/axios';

@Module({
  imports: [HttpModule.register({
    timeout: 5000,
    maxRedirects: 5,
  })],
  controllers: [GeoController],
  providers: [GeoService]
})
export class GeoModule {}

Created the controller which points to the service that's fine, and here is the service:

import { HttpService } from '@nestjs/axios';
import { Injectable } from '@nestjs/common';

@Injectable()
export class GeoService {

  constructor(private readonly httpService: HttpService) {}

  findSomething() {
    return this.httpService.get('http://urldoesntmatter.something');
  }
}

This function runs, and throws an error like this:

[Nest] 424  - 2023. 04. 27. 7:49:48   ERROR [ExceptionsHandler] Cannot read properties of undefined (reading 'emit')
TypeError: Cannot read properties of undefined (reading 'emit')
    at Object.eventHandlers.<computed> [as abort] (C:\somewhere\node_modules\follow-redirects\index.js:14:24)
    at TransformOperationExecutor.transform (C:\somewhere\node_modules\src\TransformOperationExecutor.ts:207:39)      
    at TransformOperationExecutor.transform (C:\somewhere\node_modules\src\TransformOperationExecutor.ts:327:31)      
    at TransformOperationExecutor.transform (C:\somewhere\node_modules\src\TransformOperationExecutor.ts:327:31)      
    at TransformOperationExecutor.transform (C:\somewhere\node_modules\src\TransformOperationExecutor.ts:327:31)

This error is true for any url I enter. I've googled it all day but can not resolve this issue why this happens, seems like based on the doc I didn't miss anything.

• Maybe the versions aren't compactible with each other?
• I've already tried to downgrade "follow-redirects" package also "axios" package, didn't work.
• Already tried to use directly "axios" package, also tried to use axiosRef as well. Tried different urls but even on my locally running apis it throws this error.
• Tried to modify the module to set "maxRedirects: 5" to 0. In this case there is a different error, and I also don't want to modify that value also it is 5 by default.
• Tried to modify url to use https instead of http, no success. I've checked the file as well where the error happens but I still couldn't figure out the issue.

Answer 1

I've figured out.

Based on THIS answer, I've just returning the data itself instead of the entire Axios object. This finally resolve the problem. (but this isn't in the doc. :) )

So the updated code will look like this:

import { HttpService } from '@nestjs/axios';
import { Injectable } from '@nestjs/common';

@Injectable()
export class GeoService {

  constructor(private readonly httpService: HttpService) {}

  findSomething() {
    return this.httpService.get('http://urldoesntmatter.something').pipe(
       map(response => response.data)
    );
  }
}

Thanks for your time if you already have a look and tried to resolve the problem.

Answer 2

Here is a full example from NestJs documentation which worked for me:

Since the return value of the HttpService methods is an Observable, we can use rxjs - firstValueFrom or lastValueFrom to retrieve the data of the request in the form of a promise.

import {
  catchError,
  firstValueFrom
} from 'rxjs';

@Injectable()
export class CatsService {
  private readonly logger = new Logger(CatsService.name);
  constructor(private readonly httpService: HttpService) {}

  async findAll(): Promise < Cat[] > {
    const {
      data
    } = await firstValueFrom(
      this.httpService.get < Cat[] > ('http://localhost:3000/cats').pipe(
        catchError((error: AxiosError) => {
          this.logger.error(error.response.data);
          throw 'An error happened!';
        }),
      ),
    );
    return data;
  }
}