Answer: The constructor is for DI and basic initialization; ngOnInit is for component initialization logic (API calls, data binding) when inputs are available.
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Design a scalable component library and app architecture for a large enterprise: Decoded Frontend - Angular Interview Hacking %21%21TOP%21%21
It proves you understand that change detection is the single biggest performance bottleneck. Mention ApplicationRef.tick() to manually force a full tree check. This is a !!TOP!! tier answer.
Angular interviews in 2026 reward depth over breadth. An interviewer would rather hear a detailed, nuanced answer about OnPush change detection, complete with edge cases and performance metrics, than a shallow answer that touches five separate topics. Answer: The constructor is for DI and basic
This is a classic. Always mention that a BehaviorSubject requires an initial value and emits the current value to new subscribers—a crucial detail for state management. 3. Performance Optimization: The "Pro" Level
: Angular’s default change detection strategy checks every component in the tree every time any asynchronous event occurs (clicks, timeouts, HTTP responses, etc.). As your component tree grows, this “check everything” approach becomes prohibitively expensive. Share public link Design a scalable component library
Angular runs change detection after every async event (clicks, timeouts, XHR). But what if you want to manually control it?
Other strategies:
Remember: The interviewer isn't looking for syntax. They are looking for . Show them you understand the why , not just the what .