A Deep Dive into React's Optimization Algorithms & Process

Here’s a breakdown of the key algorithms that power React:

1. Diffing Algorithm

• The diffing algorithm is crucial for React's efficiency.
• When a component's state or props change, React compares the current virtual DOM with the new virtual DOM using this algorithm.
• By examining the two trees node by node from top to bottom, it identifies differences and updates only the changed elements in the actual DOM.
• This targeted updating minimizes costly DOM manipulations, resulting in faster performance.

But to make it a more successful/optimized algorithm we need to add keys in list items.

2. Reconciliation

• Reconciliation is the process React uses to update the DOM.
• Upon changes in a component’s state or props, React generates a new virtual DOM and compares it with the previous one.
• Leveraging the diffing algorithm, React calculates the minimal set of changes needed to synchronize the real DOM with the new virtual DOM, ensuring efficient updates.

3. React Fiber

• React Fiber is a reimagined version of React’s reconciliation algorithm, introduced in React 16.
• Fiber's primary objective is to enable incremental rendering, which allows rendering work to be broken down into smaller chunks and distributed across multiple frames.
• This capability lets React pause, abort, or reuse work as new updates come in, and assign priority to different types of updates, improving responsiveness.

4. Context API

• The Context API addresses the challenge of prop drilling by enabling data sharing across all levels of a React application.
• It uses a Provider-Consumer relationship to pass data down the component tree, simplifying the management of global state without the need to pass props manually through each level.

NOTE:- It has its own problems, will update more related to this in a separate article.

Performance-impact-using-context-api

Feel free to reach out to me if you have any queries/concerns.

Comments

[Herve Tribouilloy]

This article is very interesting and well presented. I'd like to see ways to test though. Is there ways to diagnose whether a react application has diff algorithm issues?

The second question I have is regarding concurrent users: is the problem of diff algorithm exacerbated when the react site has more web visitors? If so, on what ground do you think it is the case?

thanks, great idea to nail this down!

[Ashutosh Sarangi]

Great Question, need to think / analyse how it will work more on this.

[Ashutosh Sarangi]

1. For the 1st question I doubt there would be any

I have a separate article on comparing 2 trees as like react

How to Determine 2 Binary Trees are Identical, Using Javascript

1. I think for concurrent users everyone has their own DOm to handle the diffing algorithm based on the virtual DOM.

These are my thoughts, any suggestion are welcome.