Conditional Module Loading

Load large data or modules only when a feature is activated.

Example (lazy-load animation frames):

tsx

function AnimationPlayer({
  enabled,
  setEnabled,
}: {
  enabled: boolean
  setEnabled: React.Dispatch<React.SetStateAction<boolean>>
}) {
  const [frames, setFrames] = useState<Frame[] | null>(null)

  useEffect(() => {
    if (enabled && !frames && typeof window !== 'undefined') {
      import('./animation-frames.js')
        .then((mod) => setFrames(mod.frames))
        .catch(() => setEnabled(false))
    }
  }, [enabled, frames, setEnabled])

  if (!frames) return <Skeleton />
  return <Canvas frames={frames} />
}

The typeof window !== 'undefined' check prevents bundling this module for SSR, optimizing server bundle size and build speed.