Select nothing instead of all when $or list is empty

[aebrahimian]

I have a filter like this.

  filter = {
    fields: {
      type: {
        $or: []
      }
    }
  };

and the list is bind to multi select input like this:

<ng-select [items]="items"
	           [multiple]="true"
                   [(ngModel)]="filter.fields.type.$or">
</ng-select>

which i hoped it shows all items when the list is empty and nothing is selected in input. but in this case it shows nothing