Frontend

State

The data a component remembers, which makes the UI re-render whenever it changes.

State is a component's memory — the current text in a search box, whether a modal is open, the items in a cart. When state changes, the UI automatically re-renders to match, which is the whole point: you update the data and the screen follows. A classic vibe-coding bug is putting state in the wrong place — too high and everything re-renders needlessly, too low and two components can't share it — so if the AI's UI 'won't update,' stale or misplaced state is usually why.