angular-di

Angular dependency injection using the `inject()` function replaces constructor-based injection, allowing services and dependencies to be managed efficiently within component or route scopes. It supports modern patterns like injection tokens and hierarchical providers.

Angular providers define dependency injection configurations: `useClass` instantiates a service class, `useValue` supplies a static object, and `useFactory` dynamically creates dependencies based on runtime conditions. They map to injection tokens for hierarchical provider resolution.

Angular service scoping determines dependency injection lifecycle availability. Root-level providers create singletons, component-level providers restrict dependencies to specific components, and route-level providers manage hierarchical injectors for specific routes.

Injection Tokens provide type-safe dependency injection for non-class values. Multi-providers allow multiple dependencies to be injected into a single token array, commonly used for app initializers or extending Angular configurations with multiple strategies.

Angular dependency injection supports dynamic scenarios using `runInInjectionContext` and environment injectors. These advanced patterns allow dependencies to be injected programmatically outside standard component constructors while maintaining hierarchical resolution.