[Solved] Examine this Angular component:export class SampleComponent impleme... ngOnDestroy() { // Missing unsubscribe here } }What is the likely consequence if sub.unsubscribe() is not called in ngOnDestroy? | Angular

Angular - RxJS and Observables Fundamentals

Examine this Angular component:

export class SampleComponent implements OnDestroy {
  private sub = this.api.getData().subscribe();

  ngOnDestroy() {
    // Missing unsubscribe here
  }
}

What is the likely consequence if sub.unsubscribe() is not called in ngOnDestroy?

AAngular will automatically unsubscribe, so no issues will occur

BThe subscription will continue running, potentially causing memory leaks

CThe component will throw a runtime error on destruction

DThe subscription will pause until the component is recreated

Step-by-Step Solution

Solution:

Step 1: Recognize subscription lifecycle
Subscriptions remain active unless explicitly unsubscribed.
Step 2: Understand Angular's behavior
Angular does not auto-unsubscribe for most Observables.
Step 3: Consequence of missing unsubscribe
Active subscriptions after component destruction cause memory leaks and unexpected side effects.
Final Answer:
The subscription will continue running, potentially causing memory leaks -> Option B
Quick Check:
Missing unsubscribe leads to lingering subscriptions [OK]

Quick Trick: Unsubscribe in ngOnDestroy to avoid leaks [OK]

Common Mistakes:

MISTAKES

Assuming Angular cleans up subscriptions automatically
Expecting runtime errors when unsubscribing is missed

Master "RxJS and Observables Fundamentals" in Angular

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Perf

More Angular Quizzes

Examine this Angular component:

Step 1: Recognize subscription lifecycle

Step 2: Understand Angular's behavior

Step 3: Consequence of missing unsubscribe

Final Answer:

Quick Check:

Want More Practice?