Develop Reference

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?

Trying to connect to mLab, getting Cross origin requests are only supported for protocol schemes

I know this error is common when using local files, like C:// or files://, but the thing is, Im running my app on localhost, through http-server package.
mongoose.connect('mongodb://myuser:mypswd#ds225608.mlab.com:25608/todo-list-db')

Only secure origins are allowed - Local Network

I'm getting the error: "registerServiceWorker.js:71 Error during service worker registration: DOMException: Only secure origins are allowed (see: https://www.chromium.org/Home/chromium-security/prefer-secure-origins-for-powerful-new-features)." This is on the console of a React JS web app.
I understand that to resolve this error I would need to setup HTTPS on my API server, the problem is that I am running this app on the local network and it is served through a local IP address. This web app also uses data that is only exposed locally so I can not host it externally and get an SSL cert for a domain.
From what I've read on StackOverflow I could create a self-signed certificate but this would show users an SSL error page on most browsers.
What would be the best option to resolve this issue?

CORS header 'Access-Control-Allow-Origin' missing with AngularJS Web App

I'm developing an AngularJS web app and I'm testing by running the app locally, e.g. it's not on a server. I keep running into the following error:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at (Reason: CORS header 'Access-Control-Allow-Origin' missing).1 (unknown)
My SO research tells me this is an error on the server side, but I have been successful getting data back from my iOS app running in the simulator and have used Postman with success.
Per suggestion, I'm running the app through http-server. Same issue.
I added a simple test case with the same results:
$http.get("http://www.yahoo.com")
.then(function (response) {
alert("Search Results: " + response);
}, function(error) {
alert("Could not get to Yahoo");
});
This is totally baffling.

Based on this comment:
I'm developing an AngularJS web app and I'm testing by running the app locally, e.g. it's not on a server
Then the reason this is not working is obvious: You cannot make asynchronous calls to servers in Javascript with most modern browsers by default if you are not running the javascript from a webserver (http:// instead of file:///). This is a security measure that is built into virtually all browsers. You could possibly get around this by launching the browser with certain flags; for example with Chrome you could run from the command line chrome --allow-file-access-from-files file:///[PATH_TO_FILE]
However it's recommended that you just run the javascript from a web server. This is extremely simple to do, you could use the node package http-server or Python's SimpleHTTPServer to serve the files up right from the directory they are in.

How do I start my webApp once I have the Apache Tomcat7 Server running

I am trying to host my webapp. I started with a python simpleserver, but had errors, and so with chrome and other browsers I wasn't able to send my files like a csv.
The error is XMLHttpRequest cannot load file:... Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, https, chrome-extension-resource.
And Uncaught NetworkError: Failed to execute 'send' on 'XMLHttpRequest': Failed to load .
So I tried Apache Tomcat 7 as a server, however after starting Apache7 I am confused as to how I view my webapp. I tried putting my webapp into the apache bin and calling it with localhost:8080/dataAnalyticsProject/page.html but that produces a 404 error.
My files are located in C:\Users\apt\Downloads\apache-tomcat-7.0.63-windows-x64\apache-tomcat-7.0.63\webapps\dataAnalyticsProject. How do I start up this server so that I can view my webapp?
Thanks