React can rightfully be called a game-changer JavaScript library for Drupal developers, as it can completely change the way interfaces are built. By integrating it into Drupal themes, we can enter a completely new world full of creativity and convenient functions, thus improving user experiences significantly. 
With the help of React, interfaces of websites built on Drupal will no longer be static and boring: they become real, interactive, and fast. Less words, let's learn more details about how you can benefit from using React in Drupal themes.

Why Should You Use React When Creating Drupal Themes?

There's a reason Facebook engineers decided to create their library—they wanted a tool that would handle the demands of their ambitious platform. Originally an internal tool, React was then released to the public as an open-source project. Because it was designed to handle high-stress projects like Facebook, it has pretty much proven itself capable of handling almost any other project, too.

Virtual DOM

The efficiency of the React library is attributed to its management of Document Object Model (DOM) updates. Instead of directly manipulating the DOM like most libraries do, React focuses on a lightweight virtual DOM instead. 

Component-based Architecture

Developers can easily construct modular and self-contained components that support extensive applications with ease. Each component receives parameters so you can mix and match what works best for your code structure.

Unidirectional Data Flow

For better control and predictability within applications, there's unidirectional data flow, meaning data moves from one point to another without ever flowing back upstream again after a change. With this setup, developers can easily monitor and manage data updates.

User-Friendly Development Environment

React offers you all of its features through simple concepts that won't overwhelm developers who are new to libraries like this one. On top of that, it integrates seamlessly with numerous other JavaScript libraries thanks to its large ecosystem, which was built in 2013. With such a big community contributing to the library, you'll always be able to find libraries, tutorials, and other helpful resources when things get tough.

What is React When it Comes to Drupal Themes?

React is a JavaScript library developed by Facebook. One of its biggest strengths is the way it organizes components and renders virtual DOM, making web applications more interactive and faster. By integrating React with Drupal themes, developers are able to create dynamic user interfaces that give users real-time updates and seamless interactions.

Guide: Implanting React in Drupal Themes

This tutorial will show you the process of integrating React into Drupal themes for versions 8 to 11. It allows your website to be more interactive and improves overall user experience.

Set up Your Drupal Environment

Of course, before doing anything, make sure that you already have a fully functioning Drupal website. Depending on the version you're using, install all necessary modules and dependencies.
Use Composer if your installation is based on versions 8 or 9. But if your site is based on version 10 or 11, use Drupal Console instead.

Use a Custom Drupal Theme

If you don't have one yet, create a customized theme where you can put in React components. You may base it on an existing theme or start from scratch. Just make sure that it follows the guidelines and best practices set by Drupal when it comes to theming.

Set up React Environment

You need a development environment for your newly embedded React components. There are several tools available such as Create React App, Next.js, or Webpack which can help you set up your project accordingly. Make sure that Node.js and npm (Node Package Manager) are installed before proceeding.

Develop React Components

Now is the time to go ahead and create the desired React components you want to include in your theme. Use JSX syntax as you write and put everything in a folder structure within your new project. Remember: these components should be functional and reusable whenever necessary.

Compile React Components

After creating them, compile those components into static files so they can be included later on in the theme itself. Depending on how exactly you have set up this new feature, it could involve transpiring JSX to JavaScript, bundling assets together, etc.
Just make sure that whatever compiled files come out of this process work well with what's already in your Drupal setup.

Include React Assets into Drupal Theme

Now that your React components have been compiled, include the required assets (JavaScript files, CSS files, etc.) into your existing theme. You can do this by adding them all into one single .info.yml file or using Drupal's own asset management system that allows you to properly enqueue those assets individually.

Embed React Components in Drupal Templates

The first thing here is to identify which specific Drupal templates you want to embed your newly created React components on. After choosing the right ones for the job, go ahead and put them within the Twig templates using either HTML tags or script tags. Just remember: including those components correctly requires you to input the necessary markup and data attributes so they can mount themselves properly.

Communicate Between Drupal and React

To establish good communication between these two systems, you will have to pass some data from one end to another at some point. It could also be essential to fetch additional info from Drupal APIs within your React components later on as well. If that's the case, use either GraphQL or RESTful Web Services (JSON: API), which are available through Drupal itself and allow for easy access to its data for third parties.

Test and Debug

At this point, everything should be okay if all instructions were followed correctly, but it's always a good idea to make sure by testing everything yourself first. Once done with that step, go over each of your website's pages and test them thoroughly just to confirm functionality and performance.

Deploy Your Drupal Theme

After all of these steps are finished successfully, lastly, deploy your finalized theme with embedded React components straight into the production environment.

Top 3 Strategies for Combining React with Drupal

1. Independent entities: In this method, React components are created separately from Drupal and embedded in Drupal themes using JavaScript libraries such as React or ReactDOM. 
2. Progressively decoupled architecture: The progressively decoupled architecture of Drupal allows for a mix between some parts of the frontend being powered by React while the rest is controlled by Drupal. 
3. Fully integrated approach: With the advent of modern JS frameworks into Drupal 9 and 10, developers may prefer a completely integrated approach where React is tightly coupled with the frontend framework of Drupal. This means that when integrated with react components, Drupal leverages JSON: API or GraphQL to provide an interactive experience full of rich user experiences while maintaining its CMS capabilities.

Common Problems Encountered During Integration Of Themes In React-Drupal

Despite numerous benefits associated with combining React and Drupal themes, various obstacles might be faced along the way.

• Learning curve: It is not easy for developers moving away from traditional Drupal theming to learn to use React within Drupal.
• Version compatibility: Issues could arise during integration and maintenance due to differences in compatibility between different versions of React and Drupal, as well as compatibility with other modules and libraries used.
• Performance optimization: React boosts frontend performance, but poorly implemented or inefficient code can lead to performance issues that require optimization and testing.
• Cross-origin resource sharing (CORS): Sometimes, CORS policies might restrict communication between the client side (frontend) and server side (backend). 

Real-World Drupal Sites Using React

NBCUniversal
NBCUniversal's Drupal-based websites utilize React to deliver immersive user experiences, featuring dynamic content presentation and interactive elements.

The Economist
The Economist's digital platform leverages React alongside Drupal to provide readers with a seamless browsing experience. It combines rich multimedia content with intuitive navigation.
And many more others. 

Overall, incorporating React into Drupal themes opens up a world of possibilities for business owners to create dynamic, engaging, and high-performance websites. Give it a try with the Golems company and enjoy your website!