jQuery and React are both popular JavaScript libraries for front-end development. While jQuery is a DOM manipulation library, React is a JavaScript library for building user interfaces.

Find out how to migrate an existing app from jQuery to React.

jQuery vs. React?

When it comes to choosing between jQuery and React, it depends on your needs and preferences. If you're looking for a library that is easy to use and has a large community, then jQuery is a good choice. But if you're looking for a library that is more suited for large-scale development, React is the better option.

Why Migrate From jQuery to React?

There are several reasons why you might want to migrate your app from jQuery to React.

  • React is faster than jQuery: If we're talking about raw performance, React is faster than jQuery. This is because React uses a virtual DOM, which is a JavaScript representation of the actual DOM. This means that when a user interacts with a React application, only the parts of the DOM that change will update. This is more efficient than jQuery's full DOM manipulation.
  • React is more maintainable: Another reason to migrate to React is that it is more maintainable than jQuery. This is because React components are self-contained so you can easily reuse them. This means that if you need to make a change to a React component, you can do so without affecting the rest of the codebase.
  • React is more scalable: Finally, React is more scalable than jQuery. It uses a component-based architecture, which is more scalable than jQuery's monolithic approach. This means that you can easily extend and modify a React application as necessary.
  • React has better support for unit testing: When it comes to unit testing, React has better support than jQuery. Because you can easily isolate React components, it’s easier to write unit tests for them.

How to Migrate Your App From jQuery to React

If you're planning to migrate your app from jQuery to React, there are a few things you need to keep in mind. It’s important to know what you need to begin and to get a good idea of how you can migrate individual parts of your application.

Prerequisites

Before you start the migration process, there are a few things you need to do to set things up. First, you need to create a React application using create-react-app.

After you have installed these dependencies, you need to create a file called index.js in your src directory. This file will be the entry point for your React application.

Finally, you can move on to individual parts of your codebase and update them accordingly.

1. Handling Events

In jQuery, you can attach events to elements. For example, if you have a button, you might attach a click event to it. When someone clicks the button, the event handler will run. 

        $("button").click(function() {
  // do something
});

React handles events differently. Instead of attaching events to elements, you define them in components. For example, if you have a button, you would define the click event in the component: 

        class Button extends React.Component {
  handleClick() {
    // do something
  }
  render() {
    return (
      <button onClick={this.handleClick}>
        Click me!
      </button>
    );
  }
}

Here, the Button component contains the definition of the handleClick() method. When somebody clicks the button, this method will run.

Each method has its pros and cons. In jQuery, events are easy to attach and remove. However, it can be difficult to keep track of them if you have a lot of events. In React, you define events in components, which can make them easier to keep track of. But they aren’t as easy to attach and remove.

If you're using React, you will need to update your code to use the new event handling method. For each event that you want to handle, you will need to define a method in the component. This method will run when the event triggers.

2. Effects

In jQuery, you might use the .show() or .hide() methods to show or hide an element. For example: 

        $("#element").show();

In React, you can use the useState() hook to manage state. For example, if you want to show or hide an element, you would define the state in the component: 

        import { useState } from "react";

function Component() {
  const [isShown, setIsShown] = useState(false);
  return (
    <div>
      {isShown && <div>Hello!</div>}
      <button onClick={() => setIsShown(!isShown)}>
        Toggle
      </button>
    </div>
  );
}

This code defines the isShown state variable and the setIsShown() function. React has different types of hooks that you can use in your app, of which useState is one. When a user clicks the button, the isShown state variable updates and the element displays only when appropriate.

In jQuery, effects are easy to use, and they work well. However, they can be difficult to manage if you have a lot of them. In React, effects live inside components which can make them easier to manage, if not as easy to use.

3. Data Fetching

In jQuery, you can use the $.ajax() method to fetch data. For example, if you want to fetch some JSON data, you can do so like this: 

        $.ajax({
  url: "https://example.com/data.json",
  dataType: "json",
  success: function(data) {
    // do something with the data
  }
});

In React, you can use the fetch() method to fetch data. Here’s how you can fetch JSON data using this method: 

        fetch("https://example.com/data.json")
  .then(response => response.json())
  .then(data => {
    // do something with the data
  });

In jQuery, the $.ajax() method is easy to use. However, it can be difficult to handle errors. In React, the fetch() method is more verbose, but it is easier to handle errors.

4. CSS

In jQuery, you can specify CSS by page. For example, if you want to style all the buttons on a page, you can do so by targeting the button element: 

        button {
  background-color: red;
  color: white;
}

In React, you can use CSS in different ways. One way is to use inline styles. For example, if you want to style a button, you can do so by adding the style attribute to the element: 

        <button style={{backgroundColor: 'red', color: 'white'}}>
  Click me!
</button>

Another way to style React components is using global styles. Global styles are CSS rules that you define outside a component and apply to all the components in the application. To do this, you can use a CSS-in-JS library like styled-components: 

        import styled from 'styled-components';

const Button = styled.button`
  background-color: red;
  color: white;
`;

There is no right or wrong choice between inline styles and global styles. It really depends on your requirements. In general, inline styles are easier to use for small projects. For larger projects, global styles are a better option.

Easily Deploy Your React App

One of the most significant advantages of React is that it is very easy to deploy your React App. You can deploy React on any static web server. You just need to compile your code using a tool like Webpack, and then put the resulting bundle.js file on your web server.

You can also host your React app for free on GitHub pages.