Migrating to Ionic 2 RC 0 - ngc fails

Finally, I had my app migrated to Ionic 2 RC 0. I tested the app with ionic serve, I built and deployed the app with cordova run - everything was fine.
However, since the beginning of the process was ionic serve, this meant that from an Ionic point of view, everything happened in development mode. So I had no benefit from the performance gain by using Angular's AoT (Ahead-of-time compilation).

So I tried to do a real production build with ionic build. Unfortunately, it produced an error:

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14

[12:51:11]  ionic-app-scripts 0.0.39 [12:51:11]  build prod started ... [12:51:11]  clean started ... [12:51:11]  clean finished in 7 ms [12:51:11]  copy started ... [12:51:11]  ngc started ... [12:51:11]  copy finished in 455 ms [12:51:12]  lint started ... [12:51:22]  lint finished in 9.64 s [12:51:32]  Error: Error at .../.tmp/app/app.module.ngfactory.ts:415:84 [12:51:32]  Supplied parameters do not match any signature of call target. [12:51:32]  ngc failed [12:51:32]  ionic-app-script task: "build" [12:51:32]  Error: Error

I had no idea, what was going wrong... Then I checked line 415 in app.module.ngFactory.ts (a generated file in the .tmp folder:

?

1 2 3 4

get _LoggingService_76():import46.LoggingService {   if ((this.__LoggingService_76 == (null as any))) { (this.__LoggingService_76 = new import46.LoggingService()); }     return this.__LoggingService_76; }

Ok, it has something to do with my LoggingService, which I am using as provider in app.module.ts:

?

1 2 3 4 5 6 7 8

@NgModule({   ...   providers: [     ConfigurationService     LoggingService,     ...   ] })

Then I checked the declaration of the LoggingService:

?

1 2 3 4 5

export declare class LoggingService {   private configurationService;   constructor(configurationService: ConfigurationService);   ... }

As you can see, its constructor has a parameter, but the code in app.module.ngFactory.ts is using a parameterless constructor.

One workaround could be to changed the parameter to an optional one. A better workaround is to change the declaration of the provider in app.module.ts:

?

1 2 3 4 5 6 7 8 9 10 11 12

@NgModule({   ...   providers: [     ConfigurationService,     {       provide: LoggingService,       useFactory: getLoggingService,       deps: [ConfigurationService]     },      ...   ] })

The last piece is the factory function:

?

1 2 3

export function getLoggingService(configurationService: ConfigurationService): LoggingService {   return new LoggingService(configurationService); }

That's it. Still a workaround, but working.