How to add object to constructor while executing program in Anuglar 2?

Question

Angular

I use Autocomplete so that when I enter a value, I get a filtered array, I need to use

this.filteredOptions = this.myControl.valueChanges
         .startWith(null)
         .map(val => val ? this.filter(val) : this.options.slice());

which can be added to the constructor or to ngOnInit so that they can listen to the object.
I would not have a problem if I did not need to output selects with array autocompletion, i.e.
a small example

<div *ngFor="let item of serviceRequest.items; let ind=index">

        <div [ngSwitch]="item.type">
              ....
            <div ngSwitchCase="12">
               <md-input-container>
                 <input mdInput [(ngModel)]="item.text" placeholder="{{form.items[ind].optional_select.label}}"                         [mdAutocomplete]="auto" [formControl]="myControl">
               </md-input-container>

               <md-autocomplete #auto="mdAutocomplete">
                 <md-option *ngFor="let state of item.values | async" [value]="item.text">
                   {{ state.text }}
                 </md-option>
               </md-autocomplete>
             </div>

      </div>

 </div>

where there can be several selects with auto-completion, there was an idea to immediately add, for example, 5 empty spaces to the constructor, and then use them, but this is irrational. I would like to hear your advice on what can be done in this situation)