Accessing value outside of for loop (ion-slides + button)

Ionic Framework ionic-v3
1

I have the following problem. I have a for loop which shows a list of users and i have a button (outside of the loop) which needs to perform an action on the current user on list. How is it possible to save the value of each key to a variable each time the user swipes left or right?

Here is my code (I have used some buttons inside the slides to show what i need to do with the buttons which are outside)

<ion-slides #mainSlider (ionSlideDidChange)="slideChanged()">
      <template ngFor let-user [ngForOf]="users | async">
        <template [ngIf]="user.$key !== uid">
          <ion-slide>
            <ion-card>
              <ion-card-content>
                <ion-card-title>
                  {{user.$key}}
                </ion-card-title>
              </ion-card-content>
              <ion-row *ngIf="premium">
                <ion-col (click)="like(user.$key)">
                  <button ion-button icon-left clear small>
                     <ion-icon name="add-circle"></ion-icon>
                  </button>
                </ion-col>
                </ion-col>
              </ion-row>
            </ion-card>
          </ion-slide>
        </template>
      </template>
    </ion-slides>      
    <ion-grid>
        <ion-col width-25 class="img-center" (click)="like()">
          <img src="assets/images/Premium-slide5-A.png" />
        </ion-col>
    </ion-grid>

I can get the current index of each slide but that won’t do. I have also tried to use NgModel to assign the value from each ion-slide to a variable but again not successfully…

Any help?