如何有条件地操作'@input'-

我正在通过 @Input() -我需要使用迭代器进行操作,怎么做?

这是我的代码:

@Input() events: Observable<Array<CalendarEvent>>; //required manipulation
@Input() currentEvent: ModelEvent;

clickedDate: Date;

constructor(private calendarService:CalendarService) { }

ngOnInit() {
    const headerHeight = $('.site-header').outerHeight();
    //moving content down to header
    $('body').css({paddingTop: headerHeight});

    this.calendarService.eventId.subscribe(event => {
        this.eventId = event.id;
        this.setViewDate();
    })

    // this.events.subscribe(data => console.log('data', data));

    if(this.events.length) { //how to do? //at present getting error
        <!-- do something -->
    }
}