You can implement a custom form validator by creating a function that returns a validation function.
This is the approach. We aren’t memorizing definitions. We are reverse-engineering the signal. We are hacking the interview by understanding why they ask what they ask. Decoded Frontend - Angular Interview Hacking %21%21TOP%21%21
When they say: "Let's build a mini weather dashboard" You can implement a custom form validator by
When you have a setTimeout inside a third-party library that Zone.js misses, force a local check: We are reverse-engineering the signal
"Angular uses Zone.js to detect changes automatically."
In Angular 15+, providedIn: 'root' is lazy-loaded, but if you use providedIn: 'platform' , your service survives app re-initialization. Perfect for auth services.
| If they ask this... | Don't answer this... | Say this (The Hack) | | :--- | :--- | :--- | | "How does DI work?" | "It's a tree of injectors." | "It's hierarchical. But with providedIn: 'root' and functional guards, I rarely think about trees. I think about inject() as a function in reactive contexts only." | | "What is a Directive?" | "It adds behavior to an element." | "It’s the forgotten secret to cross-cutting concerns. I don't put logic in components. I put it in structural directives to keep the DOM clean." | | "Angular vs React?" | "Angular is better." | "React has better marketing. Angular has better tooling (CLI, signals, forms). The only real difference is rendering model: React re-runs functions; Angular re-renders templates. I prefer Angular for enterprise scale." |