Angular 2 input parameters on root directive [duplicate]

Solution 1:

I think you could still use:

class App {
    constructor(elm: ElementRef) {
        this.something = elm.nativeElement.getAttribute('something'); 
    }
}

Solution 2:

This Tobias Bosch's comment has answer on your question:

The reason why this is not working is that your index.html in which you place the <app something="Test"></app> is not an angular component. Because of this, Angular won't compile this element. And Angular does not read attribute values during runtime, only during compile time, as otherwise we would get a performance hit.

So, at this moment you can't use input parameters on root element.