Sending asynchronous data to a component as an argument

Creating a custom select component with asynchronous data loading capability and passing it as a parameter is my current challenge. Here's the setup for the component:

@Component({
    selector: 'custom-select-combo',
    template:
    `<select #CustomSelectCombobox
        class="form-control"
        [(ngModel)]="selectedOption"
        (ngModelChange)="selectedOptionChange.emit($event)"
        [attr.data-live-search]="true">        
            <option *ngFor="let item of items | async" [value]="item">{{item}}</option>
    </select>`
})
export class CustomSelectComboComponent extends AppComponentBase implements OnInit, AfterViewInit {

    @ViewChild('CustomSelectCombobox') customSelectComboboxElement: ElementRef;

    @Input() selectedOption: string = undefined;
    @Input() items: string[];
    @Output() selectedOptionChange: EventEmitter<string> = new EventEmitter<string>();

    constructor(
        injector: Injector) {
        super(injector);
    }

    ngOnInit(): void {
        const self = this;
        setTimeout(() => {
            $(self.customSelectComboboxElement.nativeElement).selectpicker('refresh');
        }, 0);
    }

    ngAfterViewInit(): void {
        $(this.customSelectComboboxElement.nativeElement).selectpicker({
            iconBase: 'famfamfam-flag',
            tickIcon: 'fa fa-check'
        });
    }
}

This snippet shows how to incorporate the custom select component in an HTML file:

<div class="col-xs-6">
    <custom-select-combo [items]="tipoItems"></custom-select-combo>
</div>

As for the data loading part, I've implemented the following logic:

tipoItems = [];

constructor(
    injector: Injector,
    private _tipoDadoService: TipoDadoServiceProxy,
) {
    super(injector);
    this._tipoDadoService.getAllTipos()
        .subscribe((result) => {
            this.tipoItems = result;
        });
}

Upon testing the code, I encountered the following errors in the console:

"ERROR Error: InvalidPipeArgument: '' for pipe 'AsyncPipe'"

"ERROR TypeError: Cannot read property 'dispose' of null".

Despite reviewing various tutorials, resolving these issues still eludes me.

@edit: As requested, here is the service class:

@Injectable()
export class TipoDadoServiceProxy {
    // Implementation details of the service class...
}

Answer №1

experiment with this

on your HTML page

<div class="col-xs-6" *ngIf="(tipoDadoService.getAllTipos | async) && tipoDadoService.getAllTipos.getValue().length">
    <custom-select-combo [items]="_tipoDadoService.getAllTipos.getValue()"></custom-select-combo>
</div>

for your component

constructor( 
    public tipoDadoService: TipoDadoServiceProxy,
) { 
}

Answer №2

I highly recommend utilizing the ControlValueAccessor in this situation. By implementing a few methods, you can easily incorporate ngModel or utilize the custom component as a form control. For a detailed example, check out this resource: https://example.com/custom-component-form-control

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