How can I get number of added subscriptions?

Question

Im adding subscriptions into my instance of Subscription. How to find out how many subscriptions inside subscriptions constant?

const subscriptions = new Subscription();
...
formKeys.forEach(key => {
subscriptions.add(
    form.controls[key].valueChanges.subscribe(...)
}

full code:

Component:

@Component({
    selector: 'cts-schema-template',
    templateUrl: './schema-template.component.html',
    styleUrls: ['./schema-template.component.sass']
})
export class SchemaTemplateComponent implements OnInit, OnDestroy {
    form: FormGroup;
    subscriptions = new Subscription();
    _template: SchemaTemplate;
    @Input()
    set template(template: SchemaTemplate) {
        this._template = template;
        this.subscriptions.unsubscribe();
        this.subscriptions = new Subscription();
        this.subscriptions.add(
            this.formService.bindModelToForm(this._template, this.form)
        );
    }

    get template() {
        return this._template;
    }

    constructor(private formBuilder: FormBuilder,
                private formService: FormService
    ) {
        this.form = formBuilder.group({
            name: ['', Validators.required],
            description: ['', Validators.required],
        })
    }

    ngOnInit() {
    }

    ngOnDestroy(): void {
        this.subscriptions.unsubscribe();
    }

    get nameField(): AbstractControl {
        return this.form.controls['name'];
    }

    get descriptionField(): AbstractControl {
        return this.form.controls['description'];
    }
}

function bindModelToForm:

bindModelToForm(model: any, form: FormGroup, idFields: string[] = []): Subscription {
    this.initForm(model, form);
    if (!this.checkFieldsMatching(model, form)) {
        throw new Error('FormService -> bindModelToForm: Model and Form fields is not matching');
    }
    const subscriptions = new Subscription();
    const formKeys = Object.keys(form.controls);
    formKeys.forEach(key => {
        if (idFields.includes(key)) {
            subscriptions.add(
                form.controls[key].valueChanges.subscribe(
                    (newValue) => {
                        model[key] = newValue.id;
                    }
                )
            )
        } else {
            subscriptions.add(
                form.controls[key].valueChanges.subscribe(
                    (newValue) => {
                        model[key] = newValue;
                    }
                )
            );
        }
    });
    return subscriptions;
}

Answer 1

Try this:

this.subscriptions['_subscriptions'].length