Styles Background poner backgruond mediante styles

style-angular.txt

import { Component} from '@angular/core';
import { DomSanitizer} from '@angular/platform-browser'
@Component({
  selector: 'app-books',
  templateUrl: './books.component.html'
})
export class BooksComponent implements OnInit {
public urlImage:string;
  constructor(private _sanitizer:DomSanitizer) {  
    this.urlImage = "assets/img/project-2.jpg"   ;
  }
  public sanitizeImage(image: string) {
    return this._sanitizer.bypassSecurityTrustStyle(`url(${image})`);
  }
}
//HTML
[style.background-image]="sanitizeImage(urlImage)"