问Angular 2更改className会更改类名，然后将其删除

EN

  toggleActive(event) {
        const parentClass = event.target.parentElement
        debugger
        if (parentClass.className === 'active') {
            if (parentClass.previousElementSibling === null) {
                parentClass.nextElementSibling.className = 'active'
            } else {
                parentClass.previousElementSibling.className = 'active'
            }
            parentClass.className = ''
        } else {
            if (parentClass.previousElementSibling === null) {
                parentClass.nextElementSibling.className = ''
            } else {
                parentClass.previousElementSibling.className = ''
            }
            parentClass.className = 'active'
        }
    }

<ul class="nav nav-tabs">
    <li (click)="toggleActive($event)">
        <a href="#/detail/bopis/default/search/advanceSearch">Pick Up In Store</a>
    </li>
    <li (click)="toggleActive($event)"><a href="#/advanceSearch?BOSFS">Ship From Store</a></li>
</ul>