How to implement history.back() in AngularJS?

Angular JS is a typescript-based web application framework. It is supported by the Angular team of Google and open-source developers. It is a component-based framework allowing the developers to reuse the components created. It is well-suited for large and complex applications because of its well-defined project structure, templates, etc. In this article, we will see how to use the history.back() method in AngularJS, along with understanding it with the help of a suitable example.

The history.back() Method is one of the most common operations while navigating through URLs where it allows the developers to programmatically go to the previous page. It is provided with inbuilt HTML.

Implementing the history.back() using $window service

Window service is none other than a global window object inside the wrapper. It provides the browser-specific functionality and hence using the same, we can implement the history.back().

Syntax

window.history.back();

We will create a directive and then create a function that calls the above method. We can then use the function in a button which on pressed navigates back. This is an easy process since we do need not to import any package or library. Hence it provides no overhead since the window object is accessible globally.

Configuring the Angular Application

Step 1: Create a new project

ng new history_back_gfg

Step 2: Add routing to project

ng generate module app-routing --flat --module=app

Step 3: Create a new component, called Home and About

ng generate component about
ng generate component home

Project Structure:

Step 4: Modify the src>app>app.component.html as follows:

• app.component.html

<div>
    <h1 style="color: green;
               text-align: center;">
          Welcome to GeeksforGeeks
      </h1>
    <h3 style="text-align: center;">
          How to implement history.back() in AngularJS?
      </h3>

    <router-outlet></router-outlet>
</div>

Step 5: Modify the src>app>home>home.component.html

• home.component.html

<div>
    <h3>This is Home page</h3>
    <a routerLink="/about">About</a>
</div>

Step 6: Modify the src>app>about>about.component.html

• about.component.html

<div>
    <h3>This is About page</h3>
    <button appGoBack>Go Back</button>
</div>

Step 7: Modify src>app>app-routing.module.ts as follows:

• app-routing.module.ts

import { NgModule } from '@angular/core';
import { RouterModule, Routes } 
    from '@angular/router';
import { AppComponent } from './app.component';
import { AboutComponent } 
    from './about/about.component';
import { HomeComponent } 
    from './home/home.component';

const routes: Routes = [
    {
        path: '',
        component: HomeComponent,
    },
    {
        path: 'about',
        component: AboutComponent,
    }
];

@NgModule({
    imports: [RouterModule.forRoot(routes)],
    exports: [RouterModule]
})
export class AppRoutingModule { }

Step 8: Create a directive as follows for the back press:

ng generate directive go-back

Here, in the directive, we will override the HostListener onClick event so that the onClick of button navigates back. Here is the src>app>go-back.directive.ts

• go-back.directive.ts

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

@Directive({
    selector: '[appGoBack]'
})
export class GoBackDirective {

    constructor() { }

    @HostListener('click', ['$event'])
    onClick(event: MouseEvent) {
        event.preventDefault();
        window.history.back();
    }
}

Step 9: Run the application

ng serve --open

Output: