How to use mouseover and mouseout in Angular 6

Adding to what was already said.

if you want to *ngFor an element , and hide \ show elements in it, on hover, like you added in the comments, you should re-think the whole concept.

a more appropriate way to do it, does not involve angular at all. I would go with pure CSS instead, using its native :hover property.

something like:

App.Component.css

div span.only-show-on-hover {
    visibility: hidden;
}
div:hover span.only-show-on-hover  {
    visibility: visible;
}

App.Component.html

  <div *ngFor="let i of [1,2,3,4]" > hover me please.
    <span class="only-show-on-hover">you only see me when hovering</span>
  </div>

Demo: STACKBLITZ

The Angular6 equivalent code should be:

app.component.html

<div (mouseover)="changeText=true" (mouseout)="changeText=false">
  <span *ngIf="!changeText">Hide</span>
  <span *ngIf="changeText">Show</span>
</div>

app.component.ts

@Component({
   selector: 'app-main',
   templateUrl: './app.component.html'
})
export class AppComponent {
    changeText: boolean;
    constructor() {
       this.changeText = false;
    }
}

Notice that there is no such thing as $scope anymore as it existed in AngularJS. Its been replaced with member variables from the component class. Also, there is no scope resolution algorithm based on prototypical inheritance either - it either resolves to a component class member, or it doesn't.