devserver.js

const WebpackDevServer = require("webpack-dev-server")
const webpack = require('webpack')
const config = require('./webpack.config.js')

config.entry.client.push("webpack-dev-server/client?http://localhost:8080")
config.entry.client.push("webpack/hot/dev-server")
config.plugins.push(new webpack.HotModuleReplacementPlugin())

const compiler = webpack(config)

const server = new WebpackDevServer(compiler, {
  publicPath: config.output.publicPath,
  hot: true
})

server.listen(8080)