// utilities.service.ts

const focus: string = UtilitiesService.getAllFormErrors(formGroup)[0];


public static getAllFormErrors(formGroup: FormGroup): string[] {
    let fieldName: string[] = [];

    for (const value in formGroup.controls) {
        const ctrl = formGroup.get(value);
        if (ctrl instanceof FormGroup) {

        // tried calling recursive function here - this.getAllFormErrors(ctrl);

            // loop around new formControls in nested FormGroup
            for (const value in ctrl.controls) {

            const nestedCtrl = ctrl.get(value);
                if (nestedCtrl.errors !== null) {
                    fieldName.push(value);
                }
            }
        } else if (ctrl.errors !== null) {
            fieldName.push(value);
        }
    }
    return fieldName;
}

// expect the 'focus' variable to return the first field throwing a validation error