Tokens and injection

A token identifies a provider. AponiaJS supports:

• class constructors;
• explicit tokens created with createToken<T>().

Class injection

@Injectable()
class GreetingService {}

@Controller()
class AppController {
  constructor(private readonly greetings: GreetingService) {}
}

This requires TypeScript to emit decorator metadata.

Explicit token injection

Use @Inject() for interfaces, strings, configuration objects, or another non-class dependency:

import {
  Inject,
  Injectable,
  createToken,
  provideValue,
} from "@aponiajs/common";

interface AppConfig {
  readonly environment: string;
}

export const APP_CONFIG = createToken<AppConfig>("APP_CONFIG");

@Injectable()
class ConfigReader {
  constructor(@Inject(APP_CONFIG) readonly config: AppConfig) {}
}

const configProvider = provideValue(APP_CONFIG, {
  environment: "development",
});

Every createToken() call creates a new symbol identity. Export and reuse one token constant rather than recreating a token with the same description.

Diagnostics

If reflected constructor metadata is not a class and there is no explicit token, compilation throws a TypeError instructing you to use @Inject(token). Missing visible tokens become MISSING_PROVIDER errors.