angular: experimentalDecorators and Cannot find module 'angular2/angular2'.

From the 5 Min Quickstart guide: When I’d run,

    tsc --watch -m commonjs -t es5 --emitDecoratorMetadata app.ts

I’d get this error: error TS6064: Option ‘experimentalDecorators’ must also be specified when option ‘emitDecoratorMetadata’ is specified. So, I added --experimentalDecorators to the parameters list of the above command:

    tsc --watch -m commonjs -t es5 --emitDecoratorMetadata --experimentalDecorators app.ts

But now, I get this error in the log: app.ts(1,42): error TS2307: Cannot find module ‘angular2/angular2’.

Though it’s not causing any sort of error to the application from the client end.