Svelte vs. React: A Comprehensive Comparison

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Justin Ahinon

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Choosing the right JavaScript framework for your next project can be a daunting task . With so many options available, it's important to understand the strengths and weaknesses of each to make an informed decision. Two popular choices are Svelte and React, both of which offer unique approaches to building web applications.

  • Are you curious about how Svelte's compiler-based approach differs from React's runtime?

  • Do you wonder how reactivity works in each framework and how they handle state management?

  • Are you interested in learning how the simplicity of Svelte's code compares to React's JSX syntax?

In this article, we will dive into the key differences between Svelte and React, comparing their approaches to compilation, reactivity, simplicity, and overall developer experience . By the end, you'll have a better understanding of what sets these frameworks apart and be equipped to choose the right one for your next project.

Architectural Differences: Svelte as a compiler vs. React's runtime

Svelte's compiler-based approach

Svelte stands out among modern JavaScript frameworks due to its compiler-based architecture. When you build a Svelte application, the compiler processes your components and generates highly optimized, native JavaScript code that directly manipulates the DOM . This results in a smaller bundle size and faster rendering times as there is no need for a runtime framework to be shipped with your application.

It's important to note that Svelte offers other interesting features, which you can learn more about in this post: Svelte vs. SvelteKit: The Difference.

Here is the code generated by the Svelte compiler for the reactivity example we will see below:


React's Virtual DOM and runtime

React, on the other hand, uses a Virtual DOM to manage changes to the application's state. The Virtual DOM is an in-memory representation of the actual DOM, and React updates this virtual representation whenever a change occurs. Once the Virtual DOM has been updated, React compares it to the actual DOM and applies the minimal set of changes required, a process known as "reconciliation ."

The Virtual DOM approach allows React to batch updates and optimize rendering performance. However, this also means that React applications need to ship with a runtime framework, which can lead to larger bundle sizes compared to Svelte.

Reactivity in Svelte and React

Reactivity is a fundamental aspect of modern web development, allowing for efficient updates to the UI as the application state changes. Both Svelte and React offer unique approaches to handling reactivity, which we will explore below.

How does reactivity work in Svelte?

In Svelte, reactivity is built into the language itself. To create a reactive variable, you simply use the let keyword. Whenever the value of the reactive variable changes, Svelte automatically updates the DOM to reflect the change.

Check out this blog post by Rich Harris, the creator of Svelte, to understand the language's approach to reactivity: Svelte 3: Rethinking reactivity

Here's an example of a simple counter component in Svelte:


Svelte also provides built-in stores, which can be used for more advanced state management. Stores are essentially containers for reactive values that can be shared across multiple components . To create a store, you can use the writable function from the svelte/store module.

Here's an example of using a store in Svelte:


In the above example, the $ symbol is used by Svelte to mark a statement as reactive.

How does reactivity work in React?

React handles reactivity through its state management system. In class components, you would use the setState method to update the state and trigger a re-render. In more recent versions of React, the introduction of hooks allows for a more functional approach to state management. The useState hook is used to declare a state variable and provides a function to update its value.

Here's an example of a simple counter component in React using hooks:


For more advanced state management in React, developers often use external libraries like Redux, Jotai, or Recoil.

Comparing the Reactivity Approaches

Svelte's reactivity model is built into the language, making it straightforward to create reactive variables and update the DOM automatically. React, on the other hand, relies on its state management system, which has evolved from class components to hooks for functional components. Both frameworks provide ways to handle complex state management, with Svelte offering built-in stores and React relying on external libraries .

The choice between Svelte and React's reactivity models depends on your project's needs and your personal preference as a developer.

Simplicity and Syntax: Svelte's HTML, CSS, and JavaScript vs. React's JSX

When comparing Svelte and React, one of the most noticeable differences is in their syntax and the way they structure components . This section will showcase the syntax differences between the two frameworks and how it affects code simplicity.

Svelte's use of HTML, CSS, and JavaScript

Svelte components are written using plain HTML, CSS, and JavaScript , making them easily understandable for developers who are familiar with these languages. Each Svelte component consists of a single .svelte file, which can include a <script> tag for JavaScript, a <style> tag for CSS, and an HTML markup for the component's structure.

Here's an example of a simple Svelte component:


This syntax is intuitive and easy to read, as it closely resembles the structure of a typical HTML file.

React's Use of JSX

React components, on the other hand, are written using JSX (JavaScript XML), a syntax extension for JavaScript that allows you to write HTML-like code within your JavaScript. JSX is compiled down to JavaScript during the build process, and it is used to define the structure of React components.

Here's an example of a simple React component using JSX:


In this example, the component's styles are imported from a separate CSS file, and the className attribute is used instead of the standard class attribute to apply styles.

A comparison of the syntax and code complexity

Svelte's syntax, which relies on plain HTML, CSS, and JavaScript, can be more approachable for developers who are familiar with these languages. The structure of a Svelte component closely resembles that of an HTML file, making it easy to read and understand.

React's JSX syntax, on the other hand, might have a steeper learning curve for developers who are not familiar with the concept of mixing HTML-like code with JavaScript. However, JSX provides more flexibility in terms of logic and composition within the component.

When choosing between Svelte and React, consider how the syntax and simplicity of each framework align with your personal preferences and the needs of your project. Both frameworks have their strengths, and the choice ultimately depends on what you find most comfortable and efficient to work with.

Developer Experience: Svelte vs. React

Developer experience is an important aspect to consider when choosing a framework, as it can directly affect productivity, code maintainability, and overall enjoyment of the development process.

Svelte's Developer Experience

Svelte has garnered praise for its simplicity and ease of use, which contributes to a positive developer experience. Some aspects that developers appreciate include:

  1. Ease of learning : Svelte's syntax, which is based on plain HTML, CSS, and JavaScript, is familiar to most web developers, making it relatively easy to learn and understand.

  2. Minimal boilerplate : Svelte components require little boilerplate code, resulting in cleaner and more readable files.

  3. Reactivity : Svelte's built-in reactivity makes it easy to manage the state and update the UI automatically when the state changes.

  4. Built-in features : Svelte includes features like built-in stores and transitions, which can simplify state management and animations without the need for external libraries.

React's Developer Experience

React has been a popular choice among developers for years and offers a mature and well-documented ecosystem. Some aspects of React's developer experience include:

  1. Component-based architecture : React's component-based architecture promotes modular and reusable code, which can improve maintainability and scalability.

  2. Strong community and ecosystem : React has a large and active community, offering a wealth of resources, third-party libraries, and plugins to extend its functionality.

  3. Well-established best practices : Due to its maturity, React has a wealth of best practices and design patterns that can guide developers in building efficient and maintainable applications.

  4. Flexibility : React's JSX syntax allows for more flexibility in terms of logic and composition within components, which can lead to more expressive and powerful code.

Comparing Developer Experiences

Both Svelte and React offer distinct developer experiences that cater to different preferences and requirements. Svelte focuses on simplicity and ease of use, with an intuitive syntax and built-in features that minimize the need for external libraries. React, on the other hand, emphasizes a component-based architecture and a flexible syntax, backed by a mature ecosystem and strong community support.

Wrapping up

In this article, we've explored the differences between Svelte and React, focusing on their architecture, reactivity, syntax, and developer experience. Both frameworks have unique strengths and cater to different preferences and project requirements:

  • Svelte offers a simple and intuitive syntax based on plain HTML, CSS, and JavaScript, as well as built-in reactivity and features like stores and transitions. Its compiler-based architecture results in optimized JavaScript code, which can lead to better performance.

  • React provides a flexible and powerful syntax with JSX, along with a strong community and ecosystem that offer a wealth of resources and third-party libraries. React's virtual DOM and component-based architecture have been tried and tested, making it a popular choice for many developers.

Ultimately, the choice between Svelte and React depends on your personal preferences, development style, and project requirements. By understanding the differences and strengths of each framework, you can make an informed decision and choose the one that best aligns with your needs. As you embark on your next project, consider experimenting with both frameworks to gain firsthand experience and discover which one is the right fit for you.


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