I have been working on an app for few weeks and was getting a message to upgrade the cordova cli. As soon as I updated it, ionic has started malfunctioning.
I can no longer start new projects as Ionic start hangs in between at the poiny when npm is installing packages, I left my mac for 2 hours and it still could not finish package installation.
When I hit cntrl - c and ionic serve I get warnings Node Sass is not supported errors.unsupportedEnvironment.
I have seen this issue is very very common and no one replies on the forums for any solutions.
I was able to resolve this issue. The issue in my case was that the Ionic project was not created properly. As mentioned the Ionic start got stuck at npm installing packages, which was due to a network error. Somehow, the npm installer was unable to access the ip address to download the packages.
I got the network error when I uninstalled the ionic and then was trying to reinstall ionic.
Maybe the network error does not appear while starting the project.
So, I restarted my router and things started working again.
Hope it helps !