One solution would be to set the 'current' value when the div is clicked. Add a class when the 'current' value matches the item's value.

<div *ngFor="let item of items" 
(click)="onItemSelection(item) 
[class.current-selection]="item === currentValue">
   {{ item }}
</div>

Handle the event in your component.ts file by storing the new value:

currentValue: string;

onItemSelection(newValue: string) {
   this.currentValue = newValue;
}

Then update the look of the current item in your component.scss file:

.current-selection {
  background-color: green;
}