--- title: Functions Are Killing Your React App's Performance description: Functions in React components create performance pitfalls because each render creates new function references. Four key patterns are covered: using useMemo to... canonical: https://daily.dev/posts/functions-are-killing-your-react-app-s-performance-rbvt8opqv twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Functions Are Killing Your React App's Performance | daily.dev og:description: Functions in React components create performance pitfalls because each render creates new function references. Four key patterns are covered: using useMemo to... og:url: https://daily.dev/posts/functions-are-killing-your-react-app-s-performance-rbvt8opqv og:image: https://api.daily.dev/og/posts/rBVT8OPqV.png og:image:alt: Functions Are Killing Your React App's Performance og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Functions Are Killing Your React App's Performance **[Playful Programming](https://daily.dev/sources/playfulprogramming)** · [@crutchcorn](https://daily.dev/crutchcorn) · 18 min read · 0 upvotes · 0 comments ## Summary Functions in React components create performance pitfalls because each render creates new function references. Four key patterns are covered: using useMemo to cache expensive computed values, using useCallback to stabilize function references and prevent unnecessary child re-renders, extracting inline render functions into proper components to leverage React's reconciler, and stabilizing children-as-functions with useCallback. Each pattern is demonstrated with a shopping cart example, showing before/after code and React DevTools profiler validation. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [How to Avoid Overusing useCallback and useMemo in React](https://daily.dev/posts/how-to-avoid-overusing-usecallback-and-usememo-in-react-sjjyd2g8d) · freeCodeCamp · 11 upvotes · 0 comments --- Tags: [#javascript](https://daily.dev/tags/javascript), [#react](https://daily.dev/tags/react), [#performance](https://daily.dev/tags/performance) [View this post on daily.dev](https://daily.dev/posts/functions-are-killing-your-react-app-s-performance-rbvt8opqv) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Functions Are Killing Your React App's Performance","url":"https://daily.dev/posts/functions-are-killing-your-react-app-s-performance-rbvt8opqv","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/functions-are-killing-your-react-app-s-performance-rbvt8opqv"},"datePublished":"2026-03-16T21:46:54.045Z","dateModified":"2026-03-17T18:01:58.945Z","description":"Functions in React components create performance pitfalls because each render creates new function references. 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