[Solved] ngOnDestroy() { // missing unsubscribe } }What will happen if this component is created and destroyed multiple times without adding unsubscribe in ngOnDestroy? | Angular

Angular - RxJS and Observables Fundamentals

Consider this Angular component snippet:

export class MyComponent implements OnDestroy {
  private sub = this.service.getData().subscribe(data => console.log(data));

  ngOnDestroy() {
    // missing unsubscribe
  }
}

What will happen if this component is created and destroyed multiple times without adding unsubscribe in ngOnDestroy?

AMemory usage will increase over time due to active subscriptions not being cleaned up.

BThe component will automatically unsubscribe, so no issues occur.

CThe subscription will throw an error immediately on component destroy.

DThe component will reload data only once and then stop.

Step-by-Step Solution

Solution:

Step 1: Analyze missing unsubscribe
Without calling unsubscribe, the subscription stays active even after component destruction.
Step 2: Understand consequences
Repeated creation and destruction cause multiple active subscriptions, increasing memory use.
Final Answer:
Memory usage will increase over time due to active subscriptions not being cleaned up. -> Option A
Quick Check:
Missing unsubscribe causes memory leaks = A [OK]

Quick Trick: No unsubscribe means memory leaks grow with component reuse [OK]

Common Mistakes:

MISTAKES

Assuming Angular auto-unsubscribes
Expecting errors on destroy without unsubscribe
Thinking subscription stops automatically

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More Angular Quizzes

Consider this Angular component snippet:

Step 1: Analyze missing unsubscribe

Step 2: Understand consequences

Final Answer:

Quick Check:

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