Detect click outside Angular component

Question

import { Component, ElementRef, HostListener, Input } from '@angular/core';

@Component({
  selector: 'selector',
  template: `
    <div>
      {{text}}
    </div>
  `
})
export class AnotherComponent {
  public text: String;

  @HostListener('document:click', ['$event'])
  clickout(event) {
    if(this.eRef.nativeElement.contains(event.target)) {
      this.text = "clicked inside";
    } else {
      this.text = "clicked outside";
    }
  }

  constructor(private eRef: ElementRef) {
    this.text = 'no clicks yet';
  }
}

A working example - click here

An alternative to AMagyar's answer. This version works when you click on element that gets removed from the DOM with an ngIf.

http://plnkr.co/edit/4mrn4GjM95uvSbQtxrAS?p=preview

  private wasInside = false;
  
  @HostListener('click')
  clickInside() {
    this.text = "clicked inside";
    this.wasInside = true;
  }
  
  @HostListener('document:click')
  clickout() {
    if (!this.wasInside) {
      this.text = "clicked outside";
    }
    this.wasInside = false;
  }

Binding to document click through @Hostlistener is costly. It can and will have a visible performance impact if you overuse(for example, when building a custom dropdown component and you have multiple instances created in a form).

I suggest adding a @Hostlistener() to the document click event only once inside your main app component. The event should push the value of the clicked target element inside a public subject stored in a global utility service.

@Component({
  selector: 'app-root',
  template: '<router-outlet></router-outlet>'
})
export class AppComponent {

  constructor(private utilitiesService: UtilitiesService) {}

  @HostListener('document:click', ['$event'])
  documentClick(event: any): void {
    this.utilitiesService.documentClickedTarget.next(event.target)
  }
}

@Injectable({ providedIn: 'root' })
export class UtilitiesService {
   documentClickedTarget: Subject<HTMLElement> = new Subject<HTMLElement>()
}

Whoever is interested for the clicked target element should subscribe to the public subject of our utilities service and unsubscribe when the component is destroyed.

export class AnotherComponent implements OnInit {

  @ViewChild('somePopup', { read: ElementRef, static: false }) somePopup: ElementRef

  constructor(private utilitiesService: UtilitiesService) { }

  ngOnInit() {
      this.utilitiesService.documentClickedTarget
           .subscribe(target => this.documentClickListener(target))
  }

  documentClickListener(target: any): void {
     if (this.somePopup.nativeElement.contains(target))
        // Clicked inside  
     else
        // Clicked outside
  }

Improving @J. Frankenstein answear

  
  @HostListener('click')
  clickInside($event) {
    this.text = "clicked inside";
    $event.stopPropagation();
  }
  
  @HostListener('document:click')
  clickOutside() {
      this.text = "clicked outside";
  }

Above mentioned answers are correct but what if you are doing a heavy process after losing the focus from the relevant component. For that, I came with a solution with two flags where the focus out event process will only take place when losing the focus from relevant component only.

isFocusInsideComponent = false;
isComponentClicked = false;

@HostListener('click')
clickInside() {
    this.isFocusInsideComponent = true;
    this.isComponentClicked = true;
}

@HostListener('document:click')
clickout() {
    if (!this.isFocusInsideComponent && this.isComponentClicked) {
        // do the heavy process

        this.isComponentClicked = false;
    }
    this.isFocusInsideComponent = false;
}

Hope this will help you. Correct me If have missed anything.

ginalx's answer should be set as the default one imo: this method allows for many optimizations.

The problem

Say that we have a list of items and on every item we want to include a menu that needs to be toggled. We include a toggle on a button that listens for a click event on itself (click)="toggle()", but we also want to toggle the menu whenever the user clicks outside of it. If the list of items grows and we attach a @HostListener('document:click') on every menu, then every menu loaded within the item will start listening for the click on the entire document, even when the menu is toggled off. Besides the obvious performance issues, this is unnecessary.

You can, for example, subscribe whenever the popup gets toggled via a click and start listening for "outside clicks" only then.

isActive: boolean = false;

// to prevent memory leaks and improve efficiency, the menu
// gets loaded only when the toggle gets clicked
private _toggleMenuSubject$: BehaviorSubject<boolean>;
private _toggleMenu$: Observable<boolean>;

private _toggleMenuSub: Subscription;
private _clickSub: Subscription = null;


constructor(
 ...
 private _utilitiesService: UtilitiesService,
 private _elementRef: ElementRef,
){
 ...
 this._toggleMenuSubject$ = new BehaviorSubject(false);
 this._toggleMenu$ = this._toggleMenuSubject$.asObservable();

}

ngOnInit() {
 this._toggleMenuSub = this._toggleMenu$.pipe(
      tap(isActive => {
        logger.debug('Label Menu is active', isActive)
        this.isActive = isActive;

        // subscribe to the click event only if the menu is Active
        // otherwise unsubscribe and save memory
        if(isActive === true){
          this._clickSub = this._utilitiesService.documentClickedTarget
           .subscribe(target => this._documentClickListener(target));
        }else if(isActive === false && this._clickSub !== null){
          this._clickSub.unsubscribe();
        }

      }),
      // other observable logic
      ...
      ).subscribe();
}

toggle() {
    this._toggleMenuSubject$.next(!this.isActive);
}

private _documentClickListener(targetElement: HTMLElement): void {
    const clickedInside = this._elementRef.nativeElement.contains(targetElement);
    if (!clickedInside) {
      this._toggleMenuSubject$.next(false);
    }    
 }

ngOnDestroy(){
 this._toggleMenuSub.unsubscribe();
}

And, in *.component.html:

<button (click)="toggle()">Toggle the menu</button>

You can useclickOutside() method from https://www.npmjs.com/package/ng-click-outside package