TECH/talks: React Fiber

The Reconciliation Algorithm in React 16 and Beyond

React, the popular JavaScript library for building user interfaces, introduced a significant enhancement to its reconciliation algorithm called “React Fiber” starting from React 16. In this tech talk, we’ll dive into React Fiber and explore its key concepts for efficient UI updates.

What is React Fiber?

React Fiber is an architectural change in the way React handles the reconciliation process. It’s designed to improve the performance and responsiveness of React applications by enabling asynchronous rendering and better control over the rendering process.

Asynchronous Rendering

One of the primary benefits of React Fiber is its ability to perform asynchronous rendering. Instead of completing a full reconciliation in a single pass, React Fiber allows interruptions and prioritization of updates. This means that React can work on high-priority updates while deferring less critical ones, resulting in smoother user experiences and reduced jank.

Virtual DOM with Fiber

Like its predecessor, React Fiber also relies on the Virtual DOM. However, Fiber introduces a more efficient and flexible way to work with the Virtual DOM. It breaks the reconciliation process into smaller, manageable units called “fiber nodes,” which can be paused, aborted, or prioritized based on their importance.

Reconciliation Scheduling

React Fiber introduces a scheduler that decides when and how to work on different fiber nodes. This scheduler enables React to respond to user interactions and prioritize updates accordingly. For instance, React can prioritize rendering animations or responding to user input over less critical background updates.

Key Takeaways

• React Fiber is an architectural enhancement introduced in React 16 for reconciliation.
• Asynchronous rendering allows React to prioritize high-priority updates and improve user experience.
• Fiber introduces fiber nodes, enabling fine-grained control over reconciliation.
• A scheduler in Fiber manages the order and timing of updates, optimizing responsiveness.

In conclusion, React Fiber represents a significant advancement in React’s reconciliation algorithm, offering developers the tools needed to build highly performant and responsive web applications. By enabling asynchronous rendering, breaking work into smaller units, and introducing a scheduler, React Fiber empowers developers to create smoother user interfaces that can efficiently handle complex interactions and animations. Understanding React Fiber is essential for React developers looking to optimize their applications and provide users with a seamless browsing experience.

If you want to know more about the reconciliation algorithm, read:
https://legacy.reactjs.org/docs/reconciliation.html