5/5 Data mutation — setData()

[MohnDoe]

Parent

#6 — BarChart — reusable vertical bar chart component

What to build

setData(data: BarItem[]) method that replaces the internal data (shallow copy) and invalidates the render cache. Subsequence render() calls reflect the new data.

Acceptance criteria

• setData(newData) replaces stored data
• setData(newData) invalidates cache
• render(width) after setData returns output for new data
• Works with empty array (→ empty state shell)
• Works with single item

Blocked by

• 1/5 BarChart shell — frame, axes, empty state, caching #7