ionic CORS with Ajax call by third party library - ionic-framework

Question

When making Ajax call by third party library (plain js library, Oracle MCS),
CORS errors shown.
Origin ionic://localhost is not allowed by Access-Control-Allow-Origin.
XMLHttpRequest cannot load https://x.mobile.ocp.oraclecloud.com/mobile/platform/users/login due to access control checks
From my understanding, the webview engine thinks I'm browsing localhost for ionic pages,
ajax to else where is forbidden.
This is a common issue.
Below is the methods tried:
Add index content policy header
<meta http-equiv="Content-Security-Policy" content="default-src *;
style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline'
'unsafe-eval'">
Whitelist localhost and remote address
<allow-navigation href="https://x.mobile.ocp.oraclecloud.com:443" />
<allow-navigation href="http://localhost:8080" />
Workaround:
1. use UIWebview
not ok as it is deprecated
2. use cordova-plugin-advanced-http
not applicable as the call is made by third party
3. use ionic local proxy in ionic.config.json to redirect
not applicable as the call is made by third party thus cannot modify the call
Sample test case:
let xhr = new XMLHttpRequest();
xhr.open("POST", "https://x.mobile.ocp.oraclecloud.com/mobile/platform/users/login");
xhr.send();
Hope to see advise on making Ajax call using native Ajax method.

Answer 1

I recommend use native http :
install plugin(ionic3) :
$ ionic cordova plugin add cordova-plugin-advanced-http
$ npm install --save #ionic-native/http#4
use post method ref
Alternative link. it seem perfect because it will work in browser(use angular client) and in device use native http.