Interview Question

What is event delegation?

Delegation uses an ancestor listener to handle matching descendant events.

💡 Concept ✅ Quick Revision ⚡ JavaScript

Answer

Event delegation is a pattern where an ancestor listener handles events from descendant targets. • It commonly relies on event bubbling. • The listener inspects event.target or uses closest to identify the relevant descendant. • It reduces repeated listeners but requires careful target checks.

Example

Code

list.addEventListener('click', event => {
  const button = event.target.closest('button[data-id]');
  if (button && list.contains(button)) console.log(button.dataset.id);
});

Quick Revision

Delegation uses an ancestor listener to handle matching descendant events.

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