webpack 5 대응

우선 babel관련 친구들 babel-loader빼고 다 삭제하시고

 npm install -D @babel/core @babel/preset-env @babel/preset-react

webpack.config.js

var webpack = require('webpack')

module.exports = {
  mode: 'development',
  
  entry: './src/index.js',

  output: {
    path: __dirname + '/public/',
    filename: 'bundle.js'
  },

  devServer: {
    hot: true,
    // inline: true,
    host: '0.0.0.0',
    port: 4000,
    static: __dirname + '/public/',
  },

  module: {
    rules: [
      {
        test: /\.js$/,
        loader: 'babel-loader',
        exclude: /node_modules/,
        options: {
          cacheDirectory: true,
          presets: ['@babel/preset-env', '@babel/preset-react']
        }
      },
    ]
  },

  plugins: [
    new webpack.HotModuleReplacementPlugin()
  ]
}