So, here is my NEST JS Basic App.

./shared/utils/config/index.ts

export default  () => ({
   PORT: parseInt(process.env.PORT, 10) || 3000,
   TO_PRINT_RESPONSE: JSON.parse(process.env.TO_PRINT_RESPONSE),
});

app.module.ts

import CONFIG from './shared/utils/config/';
@Module({
      imports: [ 
        ConfigModule.forRoot({
          isGlobal: true,
          load: [ CONFIG ],
        })
      ]
      // some more Module Decorator Config
})
export class AppModule implements NestModule {
  configure(consumer: MiddlewareConsumer) {
      consumer
        .apply(AuthMiddleware)
        .forRoutes({ path: '/someurl', method: RequestMethod.ALL });
      // some more configuration code.
  }
}

main.ts

// AppModule is app.module.ts imported variable
import { ConfigService } from '@nestjs/config';

async function bootstrap() {
    const app: INestApplication = await NestFactory.create(AppModule, {
       logger: console,
    });

    const configService = app.get(ConfigService);
    console.log(typeof configService.get<Boolean>('TO_PRINT_RESPONSE'));

    /* this is ing as String even when:
     * 1. I place <Boolean> as a type (I know its of no use, since it does not change the datatype)
     * 2. But in config/index.ts I parsed it in BOOLEAN using JSON.parse()
     */  
}
bootstrap();

.env

 PORT=5000
 TO_PRINT_RESPONSE=true

Now:

1. .env is getting loaded via dotenv module as written ()
2. Kept debug inside ./shared/utils/config/index.ts and it is getting hit.

So, may someone please tell me, where am I doing wrong in reading the ENV value in proper datatype, when I loaded the JSON in proper format (./shared/utils/config/index.ts).

Thanks & Happy Coding :)

So, here is my NEST JS Basic App.

./shared/utils/config/index.ts

export default  () => ({
   PORT: parseInt(process.env.PORT, 10) || 3000,
   TO_PRINT_RESPONSE: JSON.parse(process.env.TO_PRINT_RESPONSE),
});

app.module.ts

import CONFIG from './shared/utils/config/';
@Module({
      imports: [ 
        ConfigModule.forRoot({
          isGlobal: true,
          load: [ CONFIG ],
        })
      ]
      // some more Module Decorator Config
})
export class AppModule implements NestModule {
  configure(consumer: MiddlewareConsumer) {
      consumer
        .apply(AuthMiddleware)
        .forRoutes({ path: '/someurl', method: RequestMethod.ALL });
      // some more configuration code.
  }
}

main.ts

// AppModule is app.module.ts imported variable
import { ConfigService } from '@nestjs/config';

async function bootstrap() {
    const app: INestApplication = await NestFactory.create(AppModule, {
       logger: console,
    });

    const configService = app.get(ConfigService);
    console.log(typeof configService.get<Boolean>('TO_PRINT_RESPONSE'));

    /* this is ing as String even when:
     * 1. I place <Boolean> as a type (I know its of no use, since it does not change the datatype)
     * 2. But in config/index.ts I parsed it in BOOLEAN using JSON.parse()
     */  
}
bootstrap();

.env

 PORT=5000
 TO_PRINT_RESPONSE=true

Now:

1. .env is getting loaded via dotenv module as written (https://docs.nestjs./techniques/configuration)
2. Kept debug inside ./shared/utils/config/index.ts and it is getting hit.

So, may someone please tell me, where am I doing wrong in reading the ENV value in proper datatype, when I loaded the JSON in proper format (./shared/utils/config/index.ts).

Thanks & Happy Coding :)

• javascript
• node.js
• typescript
• environment-variables
• nestjs

1 Answer 1

The problem is that Nest's ConfigService will not override the values it has read from the environment, hence their types will always default to string.

What you can do, however, is to assign the parsed values to different properties in your config-factory:

export default  () => ({
   port: parseInt(process.env.PORT, 10) || 3000,
   toPrintResponse: JSON.parse(process.env.TO_PRINT_RESPONSE),
});

If you then access those values, the types will be correct:

console.log(typeof configService.get('toPrintResponse')); // prints boolean
console.log(typeof configService.get('port')); // prints number