Migrating Your React App to Next.js

Next.js is a popular JavaScript framework for building server-rendered and statically-generated web applications. It was created by Zeit and is built on top of React, providing a simple and powerful way to build performant and scalable web apps. If you’re currently using Create React App (CRA) to build your React-based web app, you may be wondering if it’s worth the effort to switch to Next.js. In this guide, we’ll explore the benefits of using Next.js and walk through the process of migrating your React app to Next.js.

Prerequisites:

Before getting started, you’ll need to have the following software installed on your machine:

• Node.js and npm (or yarn)
• Git

You’ll also need to have a basic understanding of React and some experience building web apps with it.

Setting up Next.js:

To set up a new Next.js project, you’ll need to follow these steps:

1. Install the create-next-app tool: Run npm install -g create-next-app (or yarn global add create-next-app if you're using yarn) to install the tool globally.
2. Create a new Next.js project: Run create-next-app <project-name> to create a new Next.js project with the specified name. This will create a new directory with the given name and initialize a new Next.js project inside it.
3. Install dependencies: Change into the new project directory and run npm install (or yarn) to install the necessary dependencies.
4. Start the development server: Run npm run dev (or yarn dev) to start the development server. This will start the Next.js server and open the app in your default browser.

Migrating your React components:

Once you have a Next.js project set up, the next step is to migrate your existing React components to the new project. To do this, you’ll need to do the following:

1. Copy your React components: Move your React components from your CRA project to the /pages directory in your Next.js project. Next.js uses the /pages directory to determine which components to render for each route.
2. Modify your components: You’ll likely need to make some changes to your components to make them work with Next.js. For example, you’ll need to import the Link component from next/link to create links between pages, and you'll need to use the useRouter hook to access the router object in your components.
3. Test your components: Make sure your components are rendering correctly in the Next.js app by visiting the corresponding routes in the browser.

Routing and data fetching:

One of the key differences between CRA and Next.js is how they handle routing and data fetching. In CRA, you typically use React Router to define your routes and fetch data using an HTTP library like axios or fetch. In Next.js, routing is handled automatically based on the file structure in the /pages directory, and data fetching is done using the getServerSideProps or getStaticProps functions.

To implement routing in Next.js, you’ll need to create a new file in the /pages directory for each route in your app. For example, if you have a /about route in your CRA app, you'll need to create an `/pages/about.js` file in your Next.js project.

To fetch data in Next.js, you can use the getServerSideProps or getStaticProps functions. getServerSideProps is used to fetch data at request time, which means it will be called every time the page is visited. This is useful for dynamic data that changes often. getStaticProps is used to fetch data at build time, which means it will be called once when the app is built and the data will be included in the generated HTML for the page. This is useful for data that doesn't change frequently.

To use these functions, you’ll need to export them from your page component. Here’s an example of how to use getServerSideProps to fetch data from an API:

import axios from 'axios';
export async function getServerSideProps() {
  const res = await axios.get('https://my-api.com/data');
  const data = res.data;
  return {
    props: {
      data,
    },
  };
}
export default function Page({ data }) {
  // render data in the component
}

Deployment:

Once you’ve migrated your React app to Next.js and tested it locally, the next step is to deploy it to a hosting platform. Next.js supports a variety of hosting platforms, including:

• Vercel (formerly Zeit)
• Heroku
• GitHub Pages
• AWS
• Google Cloud Platform

To deploy your app to Vercel, you’ll need to create a Vercel account and link it to your GitHub or GitLab repository. Then, you can use the Vercel CLI to deploy your app. Here’s an example of how to do this:

1. Install the Vercel CLI: Run npm install -g vercel (or yarn global add vercel) to install the Vercel CLI globally.
2. Link your Vercel account: Run vercel login to link your Vercel account to the CLI.
3. Deploy your app: Run vercel in the root directory of your Next.js project to deploy the app. This will create a new deployment and display a URL where you can access the deployed app.

Bottom Line

In this guide, we’ve walked through the process of migrating your React app to Next.js. We’ve covered the prerequisites, setting up a new Next.js project, migrating your React components, handling routing and data fetching, and deploying your app. If you’re interested in building performant and scalable web apps with React, we recommend giving Next.js a try. With its powerful features and easy-to-use developer experience, it’s a great choice for building modern web apps.