dev-server.js

const fs = require('fs');
const path = require('path');
const webpack = require('webpack');
const { createBundleRenderer } = require('vue-server-renderer');
const clientConfig = require('./build/webpack.client.config');
const serverConfig = require('./build/webpack.server.config');
const clientCompiler = webpack(clientConfig);
const serverCompiler = webpack(serverConfig);

const app = require('express')();
const devMiddleware = require('webpack-dev-middleware')(clientCompiler, {
  publicPath: clientConfig.output.publicPath,
});
app.use(devMiddleware);
app.use(require('webpack-hot-middleware')(clientCompiler, { heartbeat: 5000 }));
clientConfig.entry.app = ['webpack-hot-middleware/client', clientConfig.entry.app];
clientConfig.plugins.push(new webpack.HotModuleReplacementPlugin());
const memory = new (require('memory-fs'));
const template = fs.readFileSync('./src/index.template.html', 'utf-8');

const ready = Promise.all([
    new Promise(resolve => { // client
      clientCompiler.plugin('done', _stats => {
        const clientManifest = JSON.parse(
          devMiddleware.fileSystem.readFileSync(
            path.resolve(__dirname, './dist/vue-ssr-client-manifest.json'), 'utf-8'
          )
        );
        resolve(clientManifest);
      });
    }),
    new Promise(resolve => { // server
      serverCompiler.outputFileSystem = memory;
      serverCompiler.watch({}, () => {
        const serverBundle = JSON.parse(
          memory.readFileSync(
            path.resolve(__dirname, './dist/vue-ssr-server-bundle.json'), 'utf-8'
          )
        );
        resolve(serverBundle);
      });
    }),
]);

app.get('*', async (request, response) => {
  const [ clientManifest, serverBundle ] = await ready;
  const renderer = createBundleRenderer(serverBundle, { clientManifest, template });
  const render = await renderer.renderToString({url: request.url, title: 'hello'});
  response.end(render);
});

app.listen(9999);