Btukfyl

I'm using the timepicker from the NG Bootstrap library but I want to switch the date when scrolling past midnight. I'm using a custom time adapter to model the date as a date rather than an NgbTimeStruct object and I'm caching the date in the adapter so when I'm converting from NgbTimeStruct it converts to the correct date.

The problem comes when I want to change the date from the component. In this case I need to call a method on the time adapter which can change the cached date, but I haven't got access to the instance of the adapter class.

I'm providing it to the component that uses it in the providers array:

providers: [

  { provide: NgbTimeAdapter, useClass: NgbTimeDateAdapter }

]

In the same component, I want to change the date by calling the NgbTimeDateAdapter.updateCachedDate method on the class, but it needs to update the cached value in the same instance as the one used by the timepicker. If I separately provide the adapter to the component I can call the method I need but it's a different instance so not much help.

@Component({

  selector: 'app-time-component',

  templateUrl: './time.component.html',

  styleUrls: ['./time.component.css'],

  providers: [

    NgbTimeDateAdapter,

    { provide: NgbTimeAdapter, useClass: NgbTimeDateAdapter }

  ]

})

export class TimeComponent implements OnInit {

  constructor (

    private ngbTimeDateAdapter: NgbTimeDateAdapter

  ) { }



  // ...



  setAsNextDay () {

    this.ngbTimeDateAdapter.updateCachedDate(1);

  }

  setAsPreviousDay () {

    this.ngbTimeDateAdapter.updateCachedDate(-1);

  }



}

How can I access the correct instance of a class that was injected using the providers array with the useClass method?

NgbTimeDateAdapter

@Injectable()

export class NgbTimeDateAdapter extends NgbTimeAdapter<Date> {

  // This class is used for converting between ngBootstrap timepicker times and JavaScript dates. As we need the date as well as well as the time, we must cache the date when first converting the time to the NgbTimeStruct and reuse it when converting the NgbTimeStruct to a date.

  cachedDate: Date;

  fromModel (value: Date): NgbTimeStruct {

    if (!value) {

      return null;

    }



    this.cachedDate = new Date(value.getTime());

    return {

      hour: value.getHours(),

      minute: value.getMinutes(),

      second: value.getSeconds()

    };

  }

  toModel (time: NgbTimeStruct): Date {

    if (!time) {

      return null;

    }



    const returnDate = this.cachedDate ? new Date(this.cachedDate.getTime()) : new Date();

    returnDate.setHours(time.hour);

    returnDate.setMinutes(time.minute);

    returnDate.setSeconds(time.second);

    returnDate.setMilliseconds(0);

    return returnDate;

  }



  updateCachedDate (offsetDays: number): void {

    // When scrolling the timepicker onto a different day, we need a way to handle it. The component with the datepicker must call this method to adjust the date as appropriate.

    if (this.cachedDate) {

      this.cachedDate.setDate(this.cachedDate.getDate() + offsetDays);

    }

  }

}