webpack.config.base.js

const HtmlWebpackPlugin = require('html-webpack-plugin');
const path = require('path');
const webpack = require('webpack');
module.exports = {
  mode: process.env.NODE_ENV || 'development',
  entry: {
    index: ['@babel/polyfill', './src/index.jsx']
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader'
        }
      },
      {
        test: /\.(css|scss)$/,
        include: [path.resolve(__dirname, './src'), /node_modules/],
        use: [
          'style-loader',
          'css-loader',
          'postcss-loader',
          {
            loader: 'sass-loader',
            options: {
              sourceMap: true
            }
          }
        ]
      },
      {
        test: /\.(woff(2)?|ttf|eot)(\?v=\d+\.\d+\.\d+)?$/,
        use: [
          {
            loader: 'file-loader',
            options: {
              name: '[name].[ext]',
              outputPath: 'fonts/'
            }
          }
        ]
      }
    ]
  },

  plugins: [
    new HtmlWebpackPlugin({
      template: './public/index.html'
    }),
    new webpack.DefinePlugin({
      'process.env.BASE_URL': JSON.stringify(
        'https://persephone-backend-staging.herokuapp.com/api/v1/'
      ),
      'process.env.API_URL': JSON.stringify('http://localhost:3000/api/v1')
    })
  ]
};