Angular interviews cover dependency injection, RxJS, change detection, and TypeScript — the framework is opinionated, so questions test whether you understand its machinery. Below are the most common with model answers. Junior: core theory, definitions, and simple practical cases.
You declare what a class needs in its constructor and Angular supplies it, rather than the class constructing its own dependencies. It exists so the same component can be given a real service in the app and a fake one in a test without changing its code. providedIn: 'root' makes a service a singleton for the whole app.
A component is a directive with a template — it renders something. A directive changes an existing element's behaviour or appearance without a template of its own. A pipe transforms a value for display. If you are adding markup it is a component, if you are decorating markup it is a directive.
A Promise resolves once. An Observable is a stream that may emit many times, can be cancelled by unsubscribing, and does nothing until subscribed. That laziness is the part people miss: an HTTP call that is never subscribed never fires, which is why a service method that returns an Observable has not made a request yet.
You have to when the stream does not complete on its own — valueChanges, a router event, an interval — otherwise the subscription outlives the component and holds it in memory. You do not for HttpClient, which completes after one emission. The async pipe unsubscribes for you, which is why it is the preferred shape.
Template-driven puts the model in the template with ngModel and suits a small form. Reactive builds the control tree in the class, which makes validation, dynamic fields and testing straightforward because the form is an object you can inspect. Anything with conditional fields or cross-field rules wants reactive.
An NgModule grouped declarations, imports and providers. Standalone components declare their own imports and remove the module layer for most cases — you import what a component uses next to the component. New code should be standalone; NgModules remain because large codebases exist.
In a real interview you speak under pressure. Cam asks these same questions, scores every answer, and shows exactly what to fix.
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