If you're working with Angular2+ instead of AngularJS, it's important to note that:
ng-hide is a directive in AngularJS and cannot be used in Angular2+. Instead, you can utilize *ngIf to conditionally render DOM elements or use [hidden] as an equivalent to ng-show in AngularJS when you want the element to be rendered but not displayed.
In your scenario, you can create a property in your .ts file:
public loading: boolean = false; // Update this property when necessary...
Then, in your .html template:
<div class="sub-menu" *ngIf="loading">
<ul>
<li><a>Search-sub</a></li>
<li><a>Search-sub</a></li>
<li><a>Search-sub</a></li>
<li><a>Search-sub</a></li>
</ul>
</div>