Q: Why should we use next js configuration file in React project? What's the main purpose using it? I need to know about the configuration file. Why we use it to react project.

A: *

*with next.js, you can write your environment variables in ".env.local" but those environment variables will be for server-side. if you want to add environment variables for your client, you add it to next.config.js


*If you want to add a new webpack plugin


*If you want to convert your app to progresive web app
 module.exports = {
    webpack: (config) => {
      // adding a webpack pugin
       config.plugins.push(new MonacoWebpackPlugin());
      return config;
    },
    // this will pass the env variable to the client side
    env: {
      AUTH0_NAMESPACE: process.env.AUTH0_NAMESPACE,
      BASE_URL: process.env.BASE_URL,
      EMAILJS_SERVICE_ID: process.env.EMAILJS_SERVICE_ID,
      EMAILJS_TEMPLATE_ID: process.env.EMAILJS_TEMPLATE_ID,
      EMAILJS_USER_ID: process.env.EMAILJS_USER_ID,
      BASE_URL: process.env.BASE_URL,

    },
    // set up for progressive app
     pwa: {
      dest: "public",
      // runtimeCaching,
      swSrc: "service-worker.js",
    },

  };


A: You need to add configuration file in next js project for custom advanced behavior of Next.js. The file next.config.js is a regular Node.js module, not a JSON file. It gets used by the Next.js server and build phases, and it's not included in the browser build
