Runtime error can't resolve all parameters for UserService: (?) - node.js

Question

I am new to ionic and I wan't my sidebar to have a header with the user profile that his/her details is shown like other similar apps depending on who logged in the app. However I encountered this error below.
Runtime error can't resolve all parameters for UserService: (?).
Here is my code below:
import { Injectable } from '#angular/core';
// import { Global } from '../../providers/global';
#Injectable()
export class UserService {
constructor( public storage: Storage
)
{
}
user: any;
token_type: any;
access_token: any;
refresh_token:any;
getAccount(): any{
return this.storage.get('user').then((value) => {
return value;
});
}
}
environment details:
cli packages: (/usr/lib/node_modules)
#ionic/cli-utils : 1.9.2
ionic (Ionic CLI) : 3.9.2
global packages:
Cordova CLI : 7.0.1
local packages:
#ionic/app-scripts : 2.0.2
Cordova Platforms : none
Ionic Framework : ionic-angular 3.5.3
System:
Node : v6.11.1
npm : 3.10.10
OS : Linux 4.10
Looking for help. Thanks in advance.

Answer 1

As pointed out in the comments, UserSerivce is not the problem itself. Instead, it is storage, that is not provided properly. Make sure, that you have imported the Storage module in your AppModule like so:
import { IonicStorageModule } from '#ionic/storage'; // <---- Add this!
#NgModule({
declarations: [
// ...
],
imports: [
BrowserModule,
IonicModule.forRoot(MyApp),
IonicStorageModule.forRoot() // <--- Add this!
],
bootstrap: [IonicApp],
entryComponents: [
// ...
],
providers: [
// ...
]
})
export class AppModule {}