Cannot Create Property 'selectedtest' On String 'test1' - Problem With Angular

I want to have multiply active buttons (if selected), and when I click on selected button, I want to remove active class (toggle). How can I do this? If I do it like below, I have

Solution 1:

problem is with your item. You are looping array which contains string values and when you want to select -> selectTest(item), you are providing a string value, which isn't a Object type and doesn't have param 'selectedTest', you should change your array to contain a list of Objects:

this.test = [ 
  { value: 'test1', isSelected: false },
  { value: 'test1', isSelected: false },
  { value: 'test1', isSelected: false }
];

also change selectTest function to:

selectTest(item) {
  item.isSelected = !item.isSelected;
};

then in html change:

<divclass="btn-group"><divclass="btn btn-outline-secondary" *ngFor="let test of tests" 
       (click)="selectTest(test)"
       [ngClass]="{ 'active': test.isSelected }">
       {{test.value}}
    </div></div>