How to seamlessly transition your project from Svelte to React

Transitioning from Svelte to React: A Developer's Guide

In the ever-evolving landscape of web development, the choice of frameworks and libraries plays a pivotal role in the success of a project. Svelte and React are two prominent players in this field, each with its own set of paradigms and best practices. Developers may consider converting from Svelte to React for various reasons, such as team familiarity with React, its extensive ecosystem, or the need for more complex state management solutions that React may handle better with libraries like Redux or Context API.

This article aims to guide developers through the process of transitioning from Svelte to React, highlighting key differences and providing insights into how to effectively adapt their codebase.

Understanding the Differences

Before diving into the conversion process, it's crucial to understand the fundamental differences between Svelte and React. Svelte is a compiler that generates efficient JavaScript code to update the DOM, while React is a library that uses a virtual DOM to determine the most efficient way to update the browser's DOM.

Svelte	React
Compiles code to update the DOM directly	Uses a virtual DOM to optimize DOM updates
Reactive variables are declared using the $: syntax	State is managed using useState or useReducer hooks
Components are single .svelte files	Components are typically .jsx or .tsx files
Stores are used for global state management	Context API, Redux, or other libraries are used for global state

Syntax Differences

When converting from Svelte to React, developers must adapt to the different syntax used by each framework. Below is a table that highlights some of these differences:

Svelte Syntax	React Syntax
`<script>` tag for logic	JavaScript directly in .jsx files
Reactive statements with `$:`	useState or useEffect hooks
Inline styles as `style` attribute	Inline styles as an object or styled-components
Event handling with `on:event`	Event handling with `onEvent` props

Converting Components

Components are the building blocks of both Svelte and React applications. However, the way they are created and managed differs significantly. Let's look at how a simple component conversion might look.

Svelte Component


<script>
  let name = 'World';
</script>

<h2>Hello {name}</h2>

React Component


import React, { useState } from 'react';

function Greeting() {
  const [name, setName] = useState('World');
  return (
    <h2>Hello {name}</h2>
  );
}

Handling State

State management is another area where Svelte and React differ. In Svelte, you can create reactive variables that automatically update the DOM when their values change. In React, you use the useState hook to create stateful variables.

Svelte State


<script>
  let count = 0;
  function increment() {
    count++;
  }
</script>

<button on:click="{increment}">Click me</button>
<p>Count: {count}</p>

React State


import React, { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0);
  function increment() {
    setCount(prevCount => prevCount + 1);
  }
  return (
    <div>
      <button onClick="{increment}">Click me</button>
      <p>Count: {count}</p>
    </div>
  );
}

Conclusion

Transitioning from Svelte to React involves understanding the conceptual and syntactical differences between the two. While Svelte offers a more straightforward approach with less boilerplate, React provides a robust ecosystem and greater flexibility in terms of state management and component lifecycle. By grasping these differences and adapting your code accordingly, you can make the switch smoothly and leverage the strengths of React in your projects.

Converting from Svelte to React Checklist

Project Setup

Initialize a new React project using Create React App or your preferred setup.
Install necessary dependencies such as react, react-dom, and any React-specific libraries you plan to use.
Remove Svelte configuration files and dependencies from your project.
Configure Babel and Webpack for React if not using Create React App.
Set up your development environment for React (e.g., ESLint, Prettier).

Component Conversion

Convert Svelte single-file components (.svelte) to React components (.jsx or .tsx).
Map Svelte's reactive statements to React's useState and useEffect hooks.
Translate Svelte's event handling to React's event handling syntax.
Adapt Svelte's slot mechanism to React's children prop.
Replace Svelte's context API with React's Context API.
Refactor Svelte stores to use React's state management solutions (e.g., useState, useReducer, Redux).
Update component styling to follow React's approach (CSS Modules, styled-components, etc.).

State Management

Identify Svelte stores and convert them to React's state management system.
Consider using Redux, MobX, or React's Context API for global state management.

Routing

Replace Svelte's routing solution with React Router.
Map routes and update links to use React Router's Link component.

Data Fetching and Side Effects

Convert Svelte's load function to React's useEffect for data fetching.
Use Axios, Fetch API, or React Query for making API calls in React components.

Testing

Update unit and integration tests to use React testing libraries (e.g., Jest, React Testing Library).
Refactor tests to accommodate changes in component structure and state management.

Build and Deployment

Update build scripts to accommodate React's build process.
Ensure continuous integration and deployment pipelines are configured for a React application.
Test the production build of your React application thoroughly.

Code Examples

Below are some code snippets to help with the conversion:

Converting a Svelte reactive statement to a React state hook:

const [count, setCount] = useState(0);

function increment() {
  setCount(prevCount => prevCount + 1);
}

Converting Svelte's event handling to React's:

button onClick={"{increment}"}+

Options

Toggles