Understanding React’s Reconciliation Process: How React Efficiently Updates the UI

Introduction

React is known for its efficient rendering mechanism, which ensures that the user interface (UI) updates seamlessly without requiring full-page reloads. The core of React’s performance lies in its reconciliation process, which is how React determines the most efficient way to update the DOM in response to changes in state or props. This process allows React to deliver fast, responsive applications while maintaining a smooth user experience.

In this blog post, we’ll dive into the React reconciliation process, explaining its underlying principles, key concepts like the Virtual DOM, diffing algorithm, and how React minimizes unnecessary renders to optimize performance.

1. What is React Reconciliation?

Reconciliation is the process by which React updates the DOM to reflect changes in the component’s state or props. React does this efficiently by comparing the current UI (the “old tree”) with the new UI (the “new tree”). It then calculates the minimal number of changes needed to update the DOM, instead of re-rendering the entire UI.

This process takes place every time a component’s state or props change, triggering a re-render. However, React uses the Virtual DOM and…