NestJS Error: "Cannot read properties of undefined (reading 'get')"

[Mercure28]

Why do I get "Cannot read properties of undefined (reading 'get')" in NestJS?

[TatyOko28]

This occurs when a service or dependency is not properly initialized.

Solution: Ensure the service is correctly injected:

@Controller("users")
export class UserController {
    constructor(private readonly userService: UserService) {}

    @Get()
    getUsers() {
        return this.userService.getAllUsers();  // Ensure userService is initialized
    }
}

Ensure UserService is declared in providers:

@Module({
  providers: [UserService],
  controllers: [UserController],
})
export class UserModule {}