Next.js next.config.js File

The next.config.js file in a Next.js application is a configuration file used to customize and extend the behavior of Next.js. It allows developers to adjust various settings such as routing, environment variables, image optimization, and more to tailor the application to their specific needs.

What is next.config.js?

The next.config.js is a configuration file used in Next.js, a popular React framework for building web applications. It allows developers to customize various settings and features of their Next.js projects, such as the build process, server configuration, asset optimization, and more.

Configuration Options

Here are some of the key configuration options that can be set in next.config.js:

• webpack: This option allows you to customize the Webpack configuration used by Next.js. Using this option, you can add or modify Webpack plugins, loaders, and other settings.
• env: This option allows you to define environment variables available in your application at runtime. You can define environment variables for different build environments (development, production, etc.) using this option.
• pageExtensions: By default, Next.js uses .js, .jsx, .ts, and .tsx files as valid pages. You can use this option to add or remove file extensions from the list of valid pages.
• target: This option specifies the target environment for the Next.js application. It can be set to “server”, “serverless”, or “experimental-serverless-trace”. The “server” target is used for traditional server-rendered applications, while the “serverless” target is used for serverless functions (such as AWS Lambda). The “experimental-serverless-trace” target is used for experimental serverless tracing.
• images: This option allows you to customize the behavior of Next.js when it comes to optimizing images. You can set options such as image quality, formats, and sizes using this option.
• basePath: This option allows you to specify a base path for your application. This is useful if you want to deploy your application to a subdirectory on your server.

Steps to Create Next.js Project

Step 1: Installation of next.js require npm and node.js. You can install node.js from here. Confirm the installation by running these commands on the terminal.

node -v
npm -v

Step 2: To create a Next.js app, open your terminal, in the directory you’d like to create the app in and run the following command:

npx create-next-app@latest folder-name

Step 3: You now have a new directory called folder-name. Let’s cd into it:

cd folder-name

Step 4: To start a development server for Next.js., run the following command:

npm run dev

Step 5: To see the website, go to the following URL from the web browser:

https://localhost:3000

Project Structure: 

NextJs Project Structure

Implementing next.config.js

We create a Next.js app that contains a next.config.js file. The next.config.js is a configuration file used in Next.js applications to customize the behavior of the Next.js build system. It is a regular Node.js module that exports an object containing various configuration options.

By default, the file contains the following code:

/** @type {import('next').NextConfig} */
const nextConfig = {
      reactStrictMode: true,
}

module.exports = nextConfig

Use Cases

Some common use cases for next.config.js include:

• Customizing web pack configurations
• Setting up environment variables
• Configuring server-side rendering
• Adding custom plugins and loaders
• Configuring image optimization and other performance optimizations

Reference: https://nextjs.org/docs/api-reference/next.config.js/introduction