[Solved] Identify the issue in this ngDoCheck implementation:ngDoCheck() { if (this.items !== this.previousItems) { this.previousItems = this.items; console.log('Items changed'); } } | Angular

Angular - Lifecycle Hooks

Identify the issue in this ngDoCheck implementation:

ngDoCheck() {
  if (this.items !== this.previousItems) {
    this.previousItems = this.items;
    console.log('Items changed');
  }
}

AIt only detects changes if the array reference changes, missing internal mutations

BIt causes an infinite loop by updating previousItems inside ngDoCheck

CIt throws an error because previousItems is not initialized

DIt incorrectly compares array lengths instead of references

Step-by-Step Solution

Solution:

Step 1: Understand reference comparison
The condition compares array references, not contents.
Step 2: Detecting internal mutations
Mutations like push/pop do not change the reference, so changes are missed.
Final Answer:
It only detects changes if the array reference changes, missing internal mutations -> Option A
Quick Check:
Reference check misses internal changes [OK]

Quick Trick: Reference check misses internal changes [OK]

Common Mistakes:

Master "Lifecycle Hooks" in Angular

9 interactive learning modes - each teaches the same concept differently

More Angular Quizzes

Identify the issue in this ngDoCheck implementation: