Angular 2 Focus on first invalid input after Click/Event

Question

I have an odd requirement and was hoping for some help.

I need to focus on the first found invalid input of a form after clicking a button (not submit). The form is rath

Answer 1

Unfortunately I can't test this at the moment, so might be a few bugs, but should be mostly there. Just add it to your form.

import {Directive, Input, HostListener} from '@angular/core';
import {NgForm} from '@angular/forms';

@Directive({ selector: '[scrollToFirstInvalid]' })
export class ScrollToFirstInvalidDirective {
  @Input('scrollToFirstInvalid') form: NgForm;
  constructor() {
  }
  @HostListener('submit', ['$event'])
  onSubmit(event) {
    if(!this.form.valid) {
      let target;
      for (var i in this.form.controls) {
        if(!this.form.controls[i].valid) {
          target = this.form.controls[i];
          break;
        }
      }
      if(target) {
        $('html,body').animate({scrollTop: $(target.nativeElement).offset().top}, 'slow');
      }
    }
  }
}

Answer 2

I recommend putting this in a service, for me it worked like this:

if (this.form.valid) {
  //submit
} else {
  let control;
  Object.keys(this.form.controls).reverse().forEach( (field) => {
    if (this.form.get(field).invalid) {
      control = this.form.get(field);
      control.markAsDirty();
    }
  });

  if(control) {
    let el = $('.ng-invalid:not(form):first');
    $('html,body').animate({scrollTop: (el.offset().top - 20)}, 'slow', () => {
      el.focus();
    });
  }
}

Answer 3

I've created an Angular directive to solve this problem. You can check it here ngx-scroll-to-first-invalid.

Steps:

1.Install the module:

npm i @ismaestro/ngx-scroll-to-first-invalid --save

2.Import the NgxScrollToFirstInvalidModule:

import {BrowserModule} from '@angular/platform-browser';
import {NgModule} from '@angular/core';
import {NgxScrollToFirstInvalidModule} from '@ismaestro/ngx-scroll-to-first-invalid';

@NgModule({
    imports: [
        BrowserModule,
        NgxScrollToFirstInvalidModule
    ],
    bootstrap: [AppComponent]
})
export class AppModule { }

3.Use the directive inside a form:

<form [formGroup]="testForm" ngxScrollToFirstInvalid>
  <input id="test-input1" type="text" formControlName="someText1">
  <button (click)="saveForm()"></button>
</form>

Hope it helps! :)