How to configure CRACO config file?

I want to configure the middleware of my craco.config.js, but I don't know have, so I want tips. My actual file is:

const {CracoAliasPlugin} = require('react-app-alias')

module.exports = {
  plugins: [
    {
      plugin: CracoAliasPlugin,
      options: {}
    }
  ],
}

I found that I need to do something:

  devServer: (devServerConfig, { env, paths }) => {
    devServerConfig = {
      onBeforeSetupMiddleware: undefined,
      onAfterSetupMiddleware: undefined,
      setupMiddlewares: (middlewares, devServer) => {
        // Define middlewares
        return middlewares;
      },
    };
    return devServerConfig;
  },

But I don't know how to use it and configure it, and I don't want to implement any middlewares for now, just let the navigation without authentication. But, I'll need them in the future, so, I want to know how to configure it and some tips on what is good to do here... also, if I just implement this the way is above it gives me error 404.

To configure devServer in your craco.config.js file, you're on the right track, but you need to make sure you're modifying it correctly to avoid the 404 error. The issue here is, you're setting the devServerConfig to an incomplete or incorrect structure. You don't need to reset devServerConfig entirely, just customize the setupMiddlewares function.

const { CracoAliasPlugin } = require('react-app-alias');

module.exports = {
  plugins: [
    {
      plugin: CracoAliasPlugin,
      options: {},
    },
  ],
  devServer: (devServerConfig) => {
    // Modify the devServer configuration
    devServerConfig.setupMiddlewares = (middlewares, devServer) => {
      // Add your custom middlewares here if needed in the future
      console.log('Setting up middlewares...');
      return middlewares;
    };

    // Remove deprecated properties (if needed for compatibility)
    delete devServerConfig.onBeforeSetupMiddleware;
    delete devServerConfig.onAfterSetupMiddleware;

    return devServerConfig;
  },
};