Contextual Dependency Injection in Functional Factories

Snippet

Contextual Dependency Injection in Functional Factories

By utilizing the inject() function within functional factories, developers can resolve dependencies outside of traditional class constructors. This promotes a more functional architecture while maintaining access to Angular's hierarchical injection system.

snippet.js
javascript
export function createDataStream() {
  const config = inject(APP_CONFIG);
  const logger = inject(LoggerService, { optional: true });
 
  return new Observable(subscriber => {
    logger?.log('Stream started');
    subscriber.next(config.endpoint);
  });
}

angular

Breakdown

const config = inject(APP_CONFIG);

Resolves a configuration token from the current injection context.

inject(LoggerService, { optional: true });

Safely attempts to retrieve a service, returning null if not found.

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Contextual Dependency Injection in Functional Factories

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