Angular use modal dialog in canDeactivate Guard service for unexpected changes (form is dirty)

Question

In my Angular 4 application, I have several components with a form, for example:

export class MyComponent implements OnInit, FormComponent {

  form: FormGroup;

  ngOnInit() {
    this.form = new FormGroup({...});
  }

they use the Guard service to prevent the loss of unconfirmed changes, so if a user tries to change the route before he asks for confirmation:

import { CanDeactivate } from '@angular/router';
import { FormGroup } from '@angular/forms';

export interface FormComponent {
  form: FormGroup;
}

export class UnsavedChangesGuardService implements CanDeactivate<FormComponent> {
  canDeactivate(component: FormComponent) {
    if (component.form.dirty) {
      return confirm(
        'The form has not been submitted yet, do you really want to leave page?'
      );
    }

    return true;
  }
}

This uses a simple dialog confirm(...)and it works just fine.

However, I would like to replace this simple dialog with a more fashionable modal dialog, for example using modal ngx-bootstrap .

How can I achieve the same result using modal instead?

Answer 1

ngx-bootstrap RxJs.

:

import { Component } from '@angular/core';
import { Subject } from 'rxjs/Subject';
import { BsModalRef } from 'ngx-bootstrap';

@Component({
  selector: 'app-confirm-leave',
  templateUrl: './confirm-leave.component.html',
  styleUrls: ['./confirm-leave.component.scss']
})
export class ConfirmLeaveComponent {

  subject: Subject<boolean>;

  constructor(public bsModalRef: BsModalRef) { }

  action(value: boolean) {
    this.bsModalRef.hide();
    this.subject.next(value);
    this.subject.complete();
  }
}

:

<div class="modal-header modal-block-primary">
  <button type="button" class="close" (click)="bsModalRef.hide()">
    <span aria-hidden="true">&times;</span><span class="sr-only">Close</span>
  </button>
  <h4 class="modal-title">Are you sure?</h4>
</div>
<div class="modal-body clearfix">
  <div class="modal-icon">
    <i class="fa fa-question-circle"></i>
  </div>
  <div class="modal-text">
    <p>The form has not been submitted yet, do you really want to leave page?</p>
  </div>
</div>
<div class="modal-footer">
  <button class="btn btn-default" (click)="action(false)">No</button>
  <button class="btn btn-primary right" (click)="action(true)">Yes</button>
</div>

, , :

import { CanDeactivate } from '@angular/router';
import { FormGroup } from '@angular/forms';
import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';
import { BsModalService } from 'ngx-bootstrap';

import { ConfirmLeaveComponent } from '.....';

export interface FormComponent {
  form: FormGroup;
}

@Injectable()
export class UnsavedChangesGuardService implements CanDeactivate<FormComponent> {

  constructor(private modalService: BsModalService) {}

  canDeactivate(component: FormComponent) {
    if (component.form.dirty) {
      const subject = new Subject<boolean>();

      const modal = this.modalService.show(ConfirmLeaveComponent, {'class': 'modal-dialog-primary'});
      modal.content.subject = subject;

      return subject.asObservable();
    }

    return true;
  }
}

app.module.ts @NgModule ConfirmLeaveComponent entryComponents.

@NgModule({
  entryComponents: [
    ConfirmLeaveComponent,
  ]
})

Answer 2

ShinDarth, , , , action() (, esc ). , , .

, bsModalService onHide :

confirmModal(text?: string): Observable<boolean> {
    const subject = new Subject<boolean>();
    const modal = this.modalService.show(ConfirmLeaveModalComponent);
    modal.content.subject = subject;
    modal.content.text = text ? text : 'Are you sure?';
    const onHideObservable = this.modalService.onHide.map(() => false);
    return merge(
      subject.asObservable(),
      onHideObservable
    );
  }

onHide , ( "" ).

Answer 3

- Ashwin, Angular Material.

StackBlitz

, "", , , . , , .

Answer 4

, , , ngx-bootstrap. , "canNavigate" . , , , . , , , "canNavigate" . , , , , queryParams, .

@Injectable()
export class AddItemsAuthenticate implements CanDeactivate<AddUniformItemComponent> {

  bsModalRef: BsModalRef;
  constructor(private router: Router,
              private dataHelper: DataHelperService,
              private modalService: BsModalService) {
  }

  canDeactivate(component: AddUniformItemComponent,
                route: ActivatedRouteSnapshot,
                state: RouterStateSnapshot,
                nextState?: RouterStateSnapshot): boolean {
    if (this.dataHelper.canNavigate === false ) {
      this.bsModalRef = this.modalService.show(ConfirmDialogComponent);
      this.bsModalRef.content.title = 'Discard Changes';
      this.bsModalRef.content.description = `You have unsaved changes. Do you want to leave this page and discard
                                            your changes or stay on this page?`;

      this.modalService.onHidden.subscribe(
        result => {
          try {
            if (this.bsModalRef && this.bsModalRef.content.confirmation) {
              this.dataHelper.canNavigate = true;
              this.dataHelper.reset();;
              const queryParams = nextState.root.queryParams;
              this.router.navigate([nextState.url.split('?')[0]],
                {
                  queryParams
                });
            }
          }catch (exception) {
            // console.log(exception);
          }
        }, error => console.log(error));
    }

    return this.dataHelper.canNavigate;

  }
}

Answer 5

Angular Material Dialog:

Modal material has "componentInstance" instead of "content" in ngx-bootstrap models:

if (component.isDirty()) {
  const subject = new Subject<boolean>();
  const modal = this.dialog.open(ConfirmationDialogComponent, {
    panelClass: 'my-panel', width: '400px', height: '400px',
  });

  modal.componentInstance.subject = subject;
  return subject.asObservable()
}
  return true;
}

Answer 6

This canDeactivate method, which works with Francesco Borzi code, simply extends the additional information provided by mitschmidt regarding pressing the outside / exit button. I just add the onHide () subscription built into the function:

canDeactivate(component: FormComponent) {
        if (component.form.dirty) {
            const subject = new Subject<boolean>();

            const modal = this.modalService.show(ConfirmLeaveComponent, { 'class': 'modal-dialog-primary' });
            modal.content.subject = subject;

            this.modalService.onHide.subscribe(hide => {
                subject.next(false);
                return subject.asObservable();
            });

            return subject.asObservable();
        }

        return true;
    }