This is bootstrap code for the drop-down. Could anyone tell what is *dropdownMenu
?
<div class="btn-group" dropdown placement="bottom right">
<button dropdownToggle type="button" class="btn btn-primary dropdown-toggle">
This dropdown's menu is right-aligned <span class="caret"></span>
</button>
<ul *dropdownMenu class="dropdown-menu dropdown-menu-right" role="menu">
<li role="menuitem"><a class="dropdown-item" href="#">Action</a></li>
<li role="menuitem"><a class="dropdown-item" href="#">Another action</a></li>
<li role="menuitem"><a class="dropdown-item" href="#">Something else here</a></li>
<li class="divider dropdown-divider"></li>
<li role="menuitem"><a class="dropdown-item" href="#">Separated link</a></li>
</ul>
</div>
We also have following code in bs-dropdown-menu.directive.ts
:
@Directive({
selector: '[bsDropdownMenu],[dropdownMenu]',
exportAs: 'bs-dropdown-menu'
})
Could anyone one tell the relationship between selector
, exportAt
and the above *dropdownMenu
?
Why are we defining selector this way(ie string selector contains two arrays) and exporting and using it different way?
According to https://angular.io/guide/structural-directives every directive marked with * is structural directive.
Structural directives are responsible for HTML layout. They shape or reshape the DOM's structure, typically by adding, removing, or manupulating elements.
Meaning just like *ngIf , it would add/remove the element from the DOM and not just hide it. So in this case the *dropdownMenu will not create the ul until the dropdown is opened, and will remove it when it's closed.
I hope this answer was clear enough.
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