How to Integrate Mixpanel with NestJS

In NestJs application you can integrate Mixpanel with these simple steps:

Install the Mixpanel library:

yarn add  mixpanel

Create a service for Mixpanel by running the following command. The service will host all Mixpanel features like init, track, people etc.

nest generate service mixpanel

Add the following code to the mixPanel.service that was just created. You can setup the ConfigService or just pass your Mixpanel project token to the init() method as shown below.

import * as Mixpanel from 'mixpanel';
import { Injectable } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';

@Injectable()
export class MixpanelService {
  private mixpanel: any;

  constructor(private configService: ConfigService) {
    this.mixpanel = Mixpanel.init(
       "mixPanel Project Token", //this.configService.get<string>('mixPanelToken'),
      {
        debug: true,
        // protocol: 'http',
      },
    );
  }

  public track(eventName: string, action: any = {}): void {
    this.mixpanel.track(eventName, action);
  }
}

To track an event in a module, add the mixPanel service to the module constructor:

  constructor(
    ....
    private readonly mixpanelService: MixpanelService,
  ) {}

example track:

    this.mixpanelService.track('Sign Up', {
        $first_name: 'John,
        $last_name: 'Doe,
        $created: new Date().toISOString(),
        type: 'patient',
        distinct_id: 'userId',
        //ip: ip.address(),
      });

That is all when integrating Mixpanel with your NestJS app using a dedicated Mixpanel service. You can find more information on Mixpanel's documentation.

FULL CODE

app.module

import { Module } from '@nestjs/common';
import { AppService } from './app.service';
import { ConfigModule } from '@nestjs/config';
import { AppController } from './app.controller';
import { MixpanelService } from './mixpanel/mixpanel.service';

@Module({
  imports: [
    ConfigModule.forRoot({
      envFilePath: [
        '.env.production',
        '.env.development',
        '.env',
      ],
      // load: [configuration],  //for env variables
      isGlobal: true,
    }),
  ],
  controllers: [AppController],
  providers: [AppService, MixpanelService],
})
export class AppModule {}

mixpanel.service

import * as Mixpanel from 'mixpanel';
import { Injectable } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';

@Injectable()
export class MixpanelService {
  private mixpanel: any;

  constructor(private configService: ConfigService) {
    this.mixpanel = Mixpanel.init(
      'mixPanel Project Token', //this.configService.get<string>('mixPanelToken'),
      {
        debug: true,
        protocol: 'http',
      },
    );
  }

  public track(eventName: string, action: any = {}): void {
    this.mixpanel.track(eventName, action);
  }
}

app.service

import * as ip from 'ip';
import { MixpanelService } from './mixpanel/mixpanel.service';
import { ForbiddenException, Injectable } from '@nestjs/common';

@Injectable()
export class AppService {
  constructor(private readonly mixpanelService: MixpanelService) {}
  async signup(dto: any) {
    try {
      this.mixpanelService.track('Sign Up', {
        $first_name: dto.firstName,
        $last_name: dto.lastName,
        $created: new Date().toISOString(),
        type: 'patient',
        distinct_id: dto.id,
        ip: ip.address(),
      });
      return {
        status: true,
        message: 'User has been created successfully',
        data: dto,
      };
    } catch (err) {
      throw new ForbiddenException({
        status: false,
        message: err.message || 'Error: user not created!',
        error: 'Bad Request',
      });
    }
  }
}

That is all folks!
Reference : Uzeyr OZ