Left file: appwork-v1_3_1/angular-starter/src/app/layout/layout-footer/layout-footer.component.ts  
Right file: appwork-v1_4_0/angular-starter/src/app/layout/layout-footer/layout-footer.component.ts  

import { Component, HostBinding } from '@angular/core';	=	import { Component, HostBinding } from '@angular/core';
import { AppService } from '../../app.service';		import { AppService } from '../../app.service';
@Component({		@Component({
selector: 'app-layout-footer',		selector: 'app-layout-footer',
templateUrl: './layout-footer.component.html',		templateUrl: './layout-footer.component.html',
styles: [':host { display: block; }']		styles: [':host { display: block; }']
})		})
export class LayoutFooterComponent {		export class LayoutFooterComponent {
@HostBinding('class.layout-footer') private hostClassMain = true;	<>	@HostBinding('class.layout-footer') hostClassMain = true;
	=
constructor(private appService: AppService) {}		constructor(private appService: AppService) {}
currentBg() {		currentBg() {
return `bg-${this.appService.layoutFooterBg}`;		return `bg-${this.appService.layoutFooterBg}`;
}		}
}		}