Develop Reference

Getting a web socket connection error when I haven't attempted to connect to anything (React)

I am adding signalR to my react project. I've installed #microsoft/signalr which seems to be working fine (after a bit of updating other packages). The issue I'm having is, before I even tried to connect to a back end the browser console is showing the following error
WebSocketClient.js:16 WebSocket connection to 'wss://localhost:65043/ws' failed:
WebSocketClient # WebSocketClient.js:16
initSocket # socket.js:21
(anonymous) # socket.js:45
I have no idea where the attempt to connect is being initiated. I'm not sure if it's even an issue but I am very new to signalR and web sockets in general so I'd just like a bit of clarification.

Expo: How to fix web push notification in development when accessing through localhost (and how to fix the `localhost` service worker)?

I am using Expo SDK Version: 36 to generate a PWA.
curl http://$LOCAL_IP:19006/expo-service-worker.js: OK 200
curl http://localhost:19006/expo-service-worker.js: FAIL => Instead of serving expo-service-worker.js it serve the static asset index.html.
It cause the following error in the console:
Failed to register service-worker DOMException: Failed to register a ServiceWorker for scope ('http://localhost:19006/') with script ('http://localhost:19006/expo-service-worker.js'): The script has an unsupported MIME type ('text/html').
The file expo-service-worker.js is not served and this is problematic when you must implement web push notification because only localhost can work without it when site is not served with HTTPS.
Related issues:
https://github.com/expo/expo-cli/issues/2063
https://github.com/expo/expo-cli/issues/2468
How can I fix it?

JavaScript 404 Error in IIS

My team is building a web application using Jquery. We are coding it with Visual Studio Code and running locally using npm's http-server.
I am trying to publish the application on a local IIS server to demo to our management team. I created a new site on IIS (for this topic, I'll call it "MyWebApplication"). I copied our code to the MyWebApplication folder under wwwroot. Our application, however, is not displaying properly from the server--it only displays some of the text, but the menu we created in JavaScript is not showing up.
Looking at the Network tab in the Chrome debugger, I do have an error:
GET http://{iisserver}/scripts/menudata.js?_=1524242509037 404 (Not Found)
The initiator is jquery-3.2.1.min.js:4.
Notice it's looking for the script in the root, http://{iisserver}/scripts/..., not in http://{iisserver}/MyWebApplication/scripts/....
If I expand the scripts folder on the Sources tab of Chrome's debugger, menudata.js and one other script related to our menu are not listed. All other .js files in the folder are.
The menu does show up if I copy my scripts folder from MyWebApplication directly to the wwwroot folder, but I shouldn't have to do that.
Are there any ideas on what I can do to make this script accessible from my IIS?
This is IIS 7.5 on Windows Server 2008 R2.
Edit:
This is a 404 log entry from the IIS log:
2018-04-23 14:29:16 x.x.x.x GET /scripts/menudata.js _=1524493754277 80 - x.x.x.x Mozilla/5.0+(Windows+NT+6.1;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/65.0.3325.181+Safari/537.36 404 0 2 187

my firebase only works when I run the page in visual studio

im making a website with firebase (users, database), it worked perfectly couple day ago but now when I opened the main page from the file explorer the firebase didn't worked but when I opened it from visual studio it worked like a magic. I also got two weird errors:
On {code: "auth/network-request-failed", message: "A network error (such as timeout, interrupted connection or unreachable host) has occurred."}
code
:
"auth/network-request-failed"
message
:
"A network error (such as timeout, interrupted connection or unreachable host) has occurred."
__proto__
:
Error
main.html:1 Failed to load https://securetoken.googleapis.com/v1/token?key=AIzaSyBqJx6CHQdHf2VibQTVPGb1NJ7oiCumK3c: Response to preflight request doesn't pass access control check: The 'Access-Control-Allow-Origin' header has a value 'null' that is not equal to the supplied origin. Origin 'null' is therefore not allowed access.
I have no idea what the problem is soI would appreciate any help or attempt to help

if you didn't install firebase CLI. install then run at root of your projec as firebase serve. And your project will be served at port 5000, so http://localhost:5000/ will serve your project with full features of firebase. For full info : https://firebase.google.com/docs/cli

Mean app login not working on heroku

I have followed many tutorials on how to get mongodb and MEAN to work on heroku, and none of them have worked for me, I keep getting the 503 application error.
First I create the app, I do heroku addons:docs mongolab in the commandline, and after that I check my config and change my code so the mongoose connection is changed to the config string like this:
mongoose.connect(process.env.MONGOLAB_URI || mongodb://example:example#ds053312.mongolab.com:53312/todolist');
the second part is just an example, the one I use is the one with my information.
So after this I push my app to heroku, but when I try to run it, it still gives me the application error, and in f12 it says it's
Failed to load resource: the server responded with a status of 503
(Service Unavailable)
https://myapp.herokuapp.com/favicon.ico
What am I doing wrong? I have tried everything and none of the tutorials are working for me
EDIT: I have managed to get rid of the error by doing the following:
$ git init
$ git add .
$ git commit -m "initial version"
$ heroku apps:create
however, now that my app loads, it appears that the login and sign up features of my app doesn't work, I fill out the sign in/log in form and submit but the page just stays where it is without changing. Is there something else I was supposed to do to get these features to work?

I came here because my Heroku - deploy Login wasn't working, but Localhost was. Turns out I forgot to change the Login POST route.