问如何从Angular 2中的可观测对象提供LOCALE_ID？

EN

import { Pipe, PipeTransform } from '@angular/core';
import { LocaleService } from 'shared/locale.service';
import { Observable } from 'rxjs/Observable';
import { formatDate } from 'somelibrary';
import 'rxjs/add/operator/map';

@Pipe({
  name: 'myDate',
  pure: false
})
export class MyDatePipe implements PipeTransform {

  constructor(private localeService: LocaleService) { }

  transform(date: string): Observable<String> {
    return this.localeService.locale$.map(locale => formatDate(date, locale));
  }
}