React Compiler: Auto Performance Optimizations in React 19
React 19 introduces Compiler which removes the need for using useMemo or useCallback
Summer is finally here in Seattle! 🌞 I’ve been busy in my garden, and I’m excited to share that I’ve harvested potatoes, carrots, strawberries, and vine leaves. Its getting so good that I might as well quit coding and become a farmer now.
On that bright note, let’s kick things off with a DevJoke:
DevJoke
Question: What was the React child component sad?
Answer: Its parent didn’t give it props
React 19 Compiler
React 19 introduces a new Compiler designed to help with performance optimization. In previous versions of React, you could manually optimize your code using useMemo and useCallback. However, with React 19, the Compiler plugin can automatically optimize your code for you.
How Does It Work?
At its core, a compiler transforms high-level code into low-level, optimized code. The React Compiler works similarly by preventing unnecessary re-renders when a parent component updates.
At its core, a compiler transforms high-level code into low-level, optimized code. The React Compiler works similarly by preventing unnecessary re-renders when a parent component updates.
For example, when <Parent /> re-renders, its entire component tree may also re-render, even if only <Parent /> itself has changed. In earlier versions of React, you’d need to manually apply memoization with useMemo(), useCallback(), or React.memo() to prevent this. With the React 19 Compiler, these optimizations are handled automatically.
The Compiler also skips expensive calculations by memoizing values or groups of values within your components and hooks. However, it’s important to note that it only memoizes calculations within a React component or hook—not every function in your application.
There’s an excellent article that Jack Herrington wrote about React Compiler that I encourage you to check out.
Monthly Fireside Chats with Shruti Kapoor: Takeaways
In this month's fireside chat, Tracy Lee shared valuable insights from her career journey. She emphasized that building a community in tech is crucial for success—it requires authenticity, active listening, and connecting with the right people. Personal struggles can teach resilience, and platforms like Twitter are powerful tools for networking. Tracy also highlighted the importance of perseverance, maintaining a positive attitude, and recognizing the opportunities available in the tech industry.