Focus Jumping Everywhere? The Curse of React key='index'
키보드 입력이 딴 데로 튄다? React key='index'의 저주
Did you silence the 'unique key prop' warning with 'index' because it was annoying? That habit is destroying your form data and driving users crazy. I share my debugging nightmare where inputs swapped values and focus jumped around, explaining specificially why 'index' keys are evil in dynamic lists.
This rule will slash red lines whenever you use index as a key.
It does allow it for static lists that never change.
But in my experience, "lists that never change" don't exist. Product Managers always change their minds.