Dynamic Dependency Injection using Functional Factories

Snippet

Dynamic Dependency Injection using Functional Factories

Angular's modern Dependency Injection allows defining providers directly within an `InjectionToken` using a factory. By using the `inject()` function inside the factory, you can dynamically resolve other dependencies at runtime. This pattern promotes clean, decoupled configurations and reduces boilerplate in the `AppConfig` or module definitions.

snippet.js
javascript
import { InjectionToken, inject } from '@angular/core';
 
export const API_CONFIG = new InjectionToken<string>('ApiConfig', {
  providedIn: 'root',
  factory: () => {
    const env = inject(ENVIRONMENT_TOKEN);
    return env.production ? 'https://api.pro.com' : 'https://api.dev.com';
  }
});

angular

Breakdown

factory: () => { ... }

Defines the logic to create the dependency value when requested.

const env = inject(ENVIRONMENT_TOKEN);

Uses the functional inject API to retrieve another token within the factory context.

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Dynamic Dependency Injection using Functional Factories

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