Error after updating ionic 4

Hi all,
I’ve this issue after updating ionic version. I cant even start my ionic project. Is there any one who can help me through this. Thank you.

$ npm list -g --depth=0


├── cordova@8.0.0

├── hoek@5.0.4

├── ionic@4.1.2

├── npm@6.4.1

├── socks@2.2.1

└── ws@3.3.2

paste here your It should be something like this today


   ionic (Ionic CLI)          : 4.1.2 (C:\Users\User\AppData\Roaming\npm\node_modules\ionic)
   Ionic Framework            : @ionic/angular 4.0.0-beta.11
   @angular-devkit/core       : 0.8.3
   @angular-devkit/schematics : 0.8.3
   @angular/cli               : 7.0.0-beta.4
   @ionic/ng-toolkit          : 1.0.8
   @ionic/schematics-angular  : 1.0.6


   cordova (Cordova CLI) : 7.0.1
   Cordova Platforms     : not available
   Cordova Plugins       : no whitelisted plugins (1 plugins total)


   NodeJS : v8.11.3 (C:\Program Files\nodejs\node.exe)
   npm    : 6.4.1
   OS     : Windows 10

I can’t even run $ ionic alone so how can i run $ ionic info. so I just list npm and show what Ive installed so far.

then restart from scratch ionic cli :

npm install -g ionic

try this
npm install -g ionic@latest cordova@latest

I did"npm install -g ionic@latest cordova@latest" several times. I even uninstall my node. and everything install from scratch. But still keep getting this issue and finally I got over after downgrading back to ionic@2.2.3.