[Solved] What is wrong with this ngOnChanges implementation?ngOnChanges(changes: SimpleChanges): void { if (changes['inputProp'].currentValue) { console.log('Input changed'); } } | Angular

Angular - Lifecycle Hooks

What is wrong with this ngOnChanges implementation?

ngOnChanges(changes: SimpleChanges): void {
  if (changes['inputProp'].currentValue) {
    console.log('Input changed');
  }
}

AIt does not check if <code>inputProp</code> actually changed

BIt should return a value instead of void

CIt should use <code>changes.inputProp.previousValue</code> instead

DIt should not use <code>SimpleChanges</code> as parameter

Step-by-Step Solution

Solution:

Step 1: Analyze the condition used
The code checks if currentValue is truthy, not if the value changed.
Step 2: Understand proper change detection
It should check if previousValue !== currentValue to confirm a change.
Final Answer:
It does not check if inputProp actually changed -> Option A
Quick Check:
Check value difference, not just truthiness [OK]

Quick Trick: Compare previous and current values to detect real changes [OK]

Common Mistakes:

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What is wrong with this ngOnChanges implementation?