onmouseenter not working angular code example

Example 1: angular mouseenter

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

Example 2: angular mouseenter

<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>