Dynamic Style Url load Angular 7

JavaScript
1

I’m working on a angular 7 project,I need to load style dynamically,Anyone suggest me
Which way is better for dynamic load style in angular 7
I use this way but not working in version 7 angular

function theme(): string[] {
  // return ['./app.component.less'] >> not find
     return ['/app.component.less']
}
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: theme()
})