Overview
This post will teach us how to recognize an event in an Angular application when a user clicks outside of a component.

Required conditions
Basic familiarity with Visual Studio Code, Angular 2 or higher, Node and NPM installed, and Bootstrap

Make an Angular Project
The command to create an Angular project is as follows.

ng new angapp

Now install Bootstrap by using the following command,
npm install bootstrap --save

Now open the styles.css file and add Bootstrap file reference. To add a reference in the styles.css file add this line.
@import '~bootstrap/dist/css/bootstrap.min.css';

Now create a new component by using the following command,
ng g c actionmenu

Now open actionmenu.component.html file and add the following code.
<div class="sidebar {{show}} panel-group" clickOutside (clickOutside)="works()">
    <div class=" panel panel-default" >
        <div>
            <div class="panel-body">Panel Body</div>
            <div class="panel-footer">Panel Footer</div>
        </div>
    </div>
</div>

Now open actionmenu.component.ts file and add the following code.
import { Component, Input } from '@angular/core';

@Component({
  selector: 'app-actionmenu',
  templateUrl: './actionmenu.component.html',
  styleUrls: ['./actionmenu.component.css']
})
export class ActionmenuComponent {
  @Input() show: boolean=true;

  works() {
    this.show = !this.show;
  }
}

Now open actionmenu.component.css file and add the following code.
.sidebar {
    display: none;
}

.true {
    display: block;
}

.false {
    display: none;
}

Now open app.component.html file and add the following code.
<div class="container" style="margin-top:10px;margin-bottom: 24px;">
  <div class="col-sm-12 btn btn-info">
    How to detect clicks outside in Angular  Application
  </div>
</div>
<div class="container">
  <button type="button" class="btn btn-success" (click)="show = !show">Primary</button>
  <app-actionmenu [show]="show"></app-actionmenu>
</div>

Now open app.component.ts file and add the following code.
import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'Angular App';
  show:boolean= false;
}

Now create a new directive by using the following command, and the following code in this directive.
ng g directive clickOutside

import { Directive, ElementRef, Input, Output, HostListener, EventEmitter } from '@angular/core';

@Directive({
    selector: '[clickOutside]'
})

export class ClickOutsideDirective {

    constructor(private elementRef: ElementRef) {}

    @Output() clickOutside: EventEmitter<any> = new EventEmitter();

    @HostListener('document: click', ['$event.target']) onMouseEnter(targetElement:any) {
        const clickInside = this.elementRef.nativeElement.contains(targetElement);
        if (!clickInside) {
            this.clickOutside.emit(null);
        }
    }
}

Now open app.module.ts and following code.
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { ActionmenuComponent } from './actionmenu/actionmenu.component';
import { ClickOutsideDirective } from './click-outside.directive';
@NgModule({
  declarations: [
    AppComponent,
    ActionmenuComponent,ClickOutsideDirective
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    FormsModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Now run the application using npm start and check the result.

Click outside anyplace in the component after clicking the button. This tutorial taught us how to detect events in the Compoent Angular application when a user clicks outside of any location.