use cors

remix-simulator/package.json

@@ -18,6 +18,7 @@
     "body-parser": "^1.18.2",
     "color-support": "^1.1.3",
     "commander": "^2.19.0",
+    "cors": "^2.8.5",
     "ethereumjs-util": "^5.1.2",
     "ethereumjs-vm": "3.0.0",
     "express": "^4.16.3",

remix-simulator/src/server.js

 const express = require('express')
+const cors = require('cors')
 const bodyParser = require('body-parser')
 const app = express()
 const expressWs = require('express-ws')
@@ -14,6 +15,7 @@ class Server {
   start (host, port) {
     expressWs(app)
 
+    app.use(cors())
     app.use(bodyParser.urlencoded({extended: true}))
     app.use(bodyParser.json())