title: Preload Based on User Intent impact: MEDIUM impactDescription: reduces perceived latency tags: bundle, preload, user-intent, hover
Preload Based on User Intent
Preload heavy bundles before they're needed to reduce perceived latency.
Example (preload on hover/focus):
tsx
function EditorButton({ onClick }: { onClick: () => void }) {
const preload = () => {
if (typeof window !== 'undefined') {
void import('./monaco-editor')
}
}
return (
<button
onMouseEnter={preload}
onFocus={preload}
onClick={onClick}
>
Open Editor
</button>
)
}
Example (preload when feature flag is enabled):
tsx
function FlagsProvider({ children, flags }: Props) {
useEffect(() => {
if (flags.editorEnabled && typeof window !== 'undefined') {
void import('./monaco-editor').then(mod => mod.init())
}
}, [flags.editorEnabled])
return <FlagsContext.Provider value={flags}>
{children}
</FlagsContext.Provider>
}
The typeof window !== 'undefined' check prevents bundling preloaded modules for SSR, optimizing server bundle size and build speed.