If you use the new 3.0.0. component router ( https://github.com/angular/vladivostok ) you can use the routerLinkActive directive. No further javascript required.
<ul class="nav navbar-nav">
<li [routerLinkActive]="['active']"> <a [routerLink]="['one']">One</a></li>
<li [routerLinkActive]="['active']"> <a [routerLink]="['second']">Second</a></li>
</ul>
I used “@angular/router”: “^3.0.0-alpha.7”