How to load data before starting the application?

Question

Angular

I use this in a lazy load module:

{
            provide: APP_INITIALIZER,
            useFactory: appInit,
            deps: [DocumentsSettings],
            multi: true,
        },

export function appInit(settings: DocumentsSettings) {
    return () => settings.init();
}

@Injectable()
export class DocumentsSettings implements Settings {
    private readonly url = `${environment.apiUrl}/documents`;
    
    public init() {
        return new Promise((resolve, reject) => {
            alert();
            resolve(true);
        });
    }
}

But there is no reaction, alert()it is not displayed.