Answer
Dependency Injection provides required objects (services) to classes instead of creating them internally.
Angular uses injectors, providers, and a hierarchical DI system. Constructor injection is the most common mechanism.
Quick Answer
Angular DI: services are registered in providers and instantiated by the Angular injector. When a component declares a dependency in its constructor, Angular looks up the injector tree for a provider. providedIn: "root" creates a singleton for the whole app. Component-level providers create a new instance per component instance. Child injectors inherit from parent injectors.
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SugharaIQ Editorial Team
Verified Answer
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Source: SugharaIQ