refactor server code into a module

remix-simulator/bin/ethsim

 #!/usr/bin/env node
 
-require('../src/server');
+const Server = require('../src/server');
+const server = new Server()
+server.start()
 

remix-simulator/src/server.js

@@ -5,27 +5,32 @@ const expressWs = require('express-ws')
 const Provider = require('./provider')
 const log = require('./utils/logs.js')
 
-expressWs(app)
+class Server {
 
-var provider = new Provider()
+  constructor() {
+    this.provider = new Provider()
+  }
+
+  start(host, port) {
+    expressWs(app)
 
-app.use(bodyParser.urlencoded({extended: true}))
-app.use(bodyParser.json())
+    app.use(bodyParser.urlencoded({extended: true}))
+    app.use(bodyParser.json())
 
-app.get('/', (req, res) => {
+    app.get('/', (req, res) => {
       res.send('Welcome to remix-simulator')
-})
+    })
 
-app.use((req, res) => {
+    app.use((req, res) => {
       provider.sendAsync(req.body, (err, jsonResponse) => {
         if (err) {
           return res.send(JSON.stringify({error: err}))
         }
         res.send(jsonResponse)
       })
-})
+    })
 
-app.ws('/', (ws, req) => {
+    app.ws('/', (ws, req) => {
       ws.on('message', function (msg) {
         provider.sendAsync(JSON.parse(msg), (err, jsonResponse) => {
           if (err) {
@@ -34,6 +39,11 @@ app.ws('/', (ws, req) => {
           ws.send(JSON.stringify(jsonResponse))
         })
       })
-})
+    })
+
+    app.listen(8545, () => log('Remix Simulator listening on port 8545!'))
+  }
+
+}
 
-app.listen(8545, () => log('Remix Simulator listening on port 8545!'))
+module.exports = Server