import { filter } from 'rxjs/operators' ; const isNotNullOrUndefined = < T > ( input ) : input is T => input !== null && input !== undefined ; export const filterNotNil = ( ) => filter ( isNotNullOrUndefined ) ; const isTruthy = < T > ( input ) : input is T => ! ! input ; export const filterTruthy = ( ) => filter ( isTruthy ) ;