react-performance

Replace sequential awaits with Promise.all for independent requests, or split sibling fetches into separate child components so React runs them in parallel. You can also start promises early and await them only where the result is used.

Use direct imports instead of barrel index files, enable Next.js Optimize Package Imports, and lazy-load heavy components with next/dynamic. Defer third-party scripts with next/script using afterInteractive or lazyOnload strategies.

Use them only for expensive computations or to preserve object identity for memoized children, not for simple primitives. If the project ships React Compiler, manual memoization becomes unnecessary since the compiler handles it automatically.

No, React.cache deduplicates calls only within a single server request render. For cross-request caching of stable data like config or lookup tables, use an LRU cache or Next.js unstable_cache instead.

Common causes include subscribing to entire store objects instead of derived booleans, passing new object or array literals as props, and defining components inside other components. Select primitive or derived values and hoist static defaults to fix this.