Btukfyl

I am working on this shopping cart module for one of my projects and this is the first time I am working on feature lie Shopping cart. Here I have a button for every item and once I click on one item I want to display the + and - buttons in order to increase/decrease the quantity for that specific item.
Now what is happening in my scenario is I am able to display buttons for all items u I am failing to add a specific item, it adds all the items and if i go to remove it doesn't do anything (It reflects all items), and quantity for that item needs to be stored/removed/updated locally. Here is my code snippets.

my .ts file

   addQuantity(quantity,counter){

        for (var key in this.storageValue){

              if(this.storageValue[key] === quantity){

                this.storageValue[key].counter += counter;

                console.log(this.storageValue[key].count);

                return;

              }

              this.counter = this.counter+1;

              this.quantities.push(quantity[key]);

              console.log(this.quantities.push(quantity[key]));

        }

      } 



      subQuantity(quantity,counter){



        for (var key in this.storageValue){

          if(this.storageValue[key] === quantity){

            this.storageValue[key].counter--;

            console.log(this.storageValue[key].counter--);

            if(this.storageValue[key]){



            }

            break;

          }



          console.log(this.storageValue[key].counter--);



    }



      }



    }

my html file

<ion-content>

<ion-icon name="add-circle" (click)="addQuantity(displayItems.ITEMID)" item-right></ion-icon>

{{counter}}

 <ion-icon name="remove-circle"(click)="subQuantity(displayItems.ITEMID)" item-right></ion-icon>



</div>



<div *ngIf="!alive"> 

<button ion-button item-end (click)="alive = !alive">Add</button>

</div>

<!-- Customisable -->

</div>

</ion-item> 

I am a beginner and learning Ionic. Your guidance will be appreciated.