1. Where does it come from?

Reconciliation is a core process in React used for efficiently updating the UI.

• Origin: As React applications became increasingly complex, there was a need for an efficient way to determine which parts of the UI needed to be updated to optimize performance.
• Comparison: Before the reconciliation process, updating the UI might have required re-rendering the entire component tree, even if there were only minor changes.

2. What is it?

Reconciliation is the process used by React to compare differences between the new and old virtual DOM trees, and determine the minimal updates needed in the actual DOM.

• Method of Solution: When the state of a component changes, React creates a new virtual DOM tree and compares it with the tree from the last render.
• Three Key Principles:
  1. Update only the elements that have differences, rather than the entire tree.
  2. Use efficient algorithms to minimize the necessary computations.
  3. Reuse existing elements as much as possible, instead of creating new ones.

Example:

Background

Imagine a list component in which some items' data have changed.

Application

React uses the reconciliation algorithm to identify the changed parts and updates only those parts of the DOM, rather than the entire list.

3. Where is it going?

• Limitations: While the reconciliation algorithm is efficient, it's not perfect. In some cases, it may not identify all the optimal paths for updates.
• Direction for Optimization: Continuously improve the reconciliation algorithm to better identify and handle various update scenarios.
• Future Development: The React team and community may continue to explore new algorithms and strategies to further enhance the performance and accuracy of the reconciliation process.