fix: re-add express server (#739)

express-server.js

@@ -0,0 +1,22 @@
+const express = require('express')
+const fs = require('fs')
+const path = require('path')
+const history = require('connect-history-api-fallback')
+const app = express()
+const ip = process.env.EXPLORER_HOST || '127.0.0.1'
+const port = process.env.EXPLORER_PORT || 4200
+
+// Web Server
+const distPath = path.join(__dirname + '/dist/')
+if (fs.existsSync(distPath)) {
+const staticFileMiddleware = express.static(distPath)
+app.use(staticFileMiddleware)
+app.use(history())
+app.use(staticFileMiddleware)
+app.get('/', function (req, res) {
+    res.render(path.join(distPath + '/index.html'))
+})
+const server = app.listen(port, ip)
+} else {
+    throw new Error('No Dist Path - please build')
+}