How to inject window into a service?

Question

I'm writing an Angular 2 service in TypeScript that will make use of localstorage. I want to inject a reference to the browser window object into my service since I don't want to reference any global variables like Angular 1.x $window.

How do I do that?

Answer 1

You can get window from injected document.

import { Inject } from '@angular/core';
import { DOCUMENT } from '@angular/common';

export class MyClass {

  private window: Window;

  constructor(@Inject(DOCUMENT) private document: Document) {
     this.window = this.document.defaultView;
  }

  check() {
    console.log(this.document);
    console.log(this.window);
  }

}

If you have custom properties on window, you can use your own interface

import { Inject } from '@angular/core';
import { DOCUMENT } from '@angular/common';

export interface CustomWindow extends Window {
  $: JQuery
  customProperty: boolean;
}

export class MyClass {

  private window: CustomWindow;

  constructor(@Inject(DOCUMENT) private document: Document) {
     this.window = <any>this.document.defaultView;
  }

  check() {
    console.log(this.document);
    console.log(this.window);
  }

}

Answer 2

Declare a provider into your module:

  providers: [
    { provide: Window, useValue: window }
  ]

Into a component or service, inject:

constructor(private window: Window)

You may access properties:

console.log(this.window.document);

Or create new values:

(<any>this.window).MyNewValue = 'John Doe' ;

Answer 3

If you need to inject the window because you do really need properties belonging to the "window", just create a service as follow

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class WindowService {
  public getInstance(): Window {
    return window;
  }
}

Here is an example where it becomes easy to mock WindowService for testing purpose:

export class AnotherService {
  constructor(private windowService: WindowService) {}

  public hasPreviousPage(): boolean {
    return this.windowService.getInstance().history.length > 2;
  }
}

If however you are using window to then get a globally defined variable, I would recommend at first using globalThis instead. Then, typing the global is a matter of typescript module, in short: Do something like this:

Declare this ambient context this somewhere

declare global {
  function hello():string;
}

Then ts won't complain for the following code:

globalThis.hello(); // best way
window.hello(); // okay but window could be undefined in tests, workers or headless nodejs

Note that you still need to add the implementation of hello() globally somewhere.

Of course you could also (but I DO NOT recommend) use the following dirty trick:

import { Injectable } from '@angular/core';

interface ExtraParams {
hello:() => string;
}

@Injectable({
  providedIn: 'root',
})
export class WindowService {
  public getInstance(): Window & ExtraParams {
    return window as unknown as Window & ExtraParams;
  }
}

Answer 4

Here's another solution I came up recently after I got tired of getting defaultView from DOCUMENT built-in token and checking it for null:

import {DOCUMENT} from '@angular/common';
import {inject, InjectionToken} from '@angular/core';

export const WINDOW = new InjectionToken<Window>(
    'An abstraction over global window object',
    {
        factory: () => {
            const {defaultView} = inject(DOCUMENT);

            if (!defaultView) {
                throw new Error('Window is not available');
            }

            return defaultView;
        }
    });

Note: I have released this token with many other global object accessors as a tiny library available here: https://github.com/ng-web-apis/common

Check out the rest of the org for many other native API libraries for Angular: https://github.com/ng-web-apis

Answer 5

It's also a good idea to mark the DOCUMENT as optional. Per the Angular docs:

Document might not be available in the Application Context when Application and Rendering Contexts are not the same (e.g. when running the application into a Web Worker).

Here's an example of using the DOCUMENT to see whether the browser has SVG support:

import { Optional, Component, Inject } from '@angular/core';
import { DOCUMENT } from '@angular/common'

...

constructor(@Optional() @Inject(DOCUMENT) document: Document) {
   this.supportsSvg = !!(
   document &&
   document.createElementNS &&
   document.createElementNS('http://www.w3.org/2000/svg', 'svg').createSVGRect
);

Answer 6

Actually its very simple to access window object here is my basic component and i tested it its working

import { Component, OnInit,Inject } from '@angular/core';
import {DOCUMENT} from '@angular/platform-browser';

@Component({
  selector: 'app-verticalbanners',
  templateUrl: './verticalbanners.component.html',
  styleUrls: ['./verticalbanners.component.css']
})
export class VerticalbannersComponent implements OnInit {

  constructor(){ }

  ngOnInit() {
    console.log(window.innerHeight );
  }

}

Answer 7

Keep it simple, folks!

export class HeroesComponent implements OnInit {
  heroes: Hero[];
  window = window;
}

<div>{{window.Object.entries({ foo: 1 }) | json}}</div>

Answer 8

This is working for me currently (2018-03, angular 5.2 with AoT, tested in angular-cli and a custom webpack build):

First, create an injectable service that provides a reference to window:

import { Injectable } from '@angular/core';

// This interface is optional, showing how you can add strong typings for custom globals.
// Just use "Window" as the type if you don't have custom global stuff
export interface ICustomWindow extends Window {
    __custom_global_stuff: string;
}

function getWindow (): any {
    return window;
}

@Injectable()
export class WindowRefService {
    get nativeWindow (): ICustomWindow {
        return getWindow();
    }
}

Now, register that service with your root AppModule so it can be injected everywhere:

import { WindowRefService } from './window-ref.service';

@NgModule({        
  providers: [
    WindowRefService 
  ],
  ...
})
export class AppModule {}

and then later on where you need to inject window:

import { Component} from '@angular/core';
import { WindowRefService, ICustomWindow } from './window-ref.service';

@Component({ ... })
export default class MyCoolComponent {
    private _window: ICustomWindow;

    constructor (
        windowRef: WindowRefService
    ) {
        this._window = windowRef.nativeWindow;
    }

    public doThing (): void {
        let foo = this._window.XMLHttpRequest;
        let bar = this._window.__custom_global_stuff;
    }
...

You may also wish to add nativeDocument and other globals to this service in a similar way if you use these in your application.

---

edit: Updated with Truchainz suggestion. edit2: Updated for angular 2.1.2 edit3: Added AoT notes edit4: Adding any type workaround note edit5: Updated solution to use a WindowRefService which fixes an error I was getting when using previous solution with a different build edit6: adding example custom Window typing

Answer 9

Getting window object via DI(Dependency Injection) is not a good idea when global variables are accessible throughout the application.

But if you don't want to use window object then you can also use self keyword which also points to window object.

Answer 10

There is an opportunity for direct access to the object of window through the document

document.defaultView == window

Answer 11

You can use NgZone on Angular 4:

import { NgZone } from '@angular/core';

constructor(private zone: NgZone) {}

print() {
    this.zone.runOutsideAngular(() => window.print());
}

Answer 12

It is enough to do

export class AppWindow extends Window {} 

and do

{ provide: 'AppWindow', useValue: window } 

to make AOT happy

Answer 13

@maxisam thanks for ngx-window-token. I was doing something similar but switched to yours. This is my service for listening to window resize events and notifying subscribers.

import { Inject, Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/fromEvent';
import { WINDOW } from 'ngx-window-token';


export interface WindowSize {
    readonly width: number;
    readonly height: number;
}

@Injectable()
export class WindowSizeService {

    constructor( @Inject(WINDOW) private _window: any ) {
        Observable.fromEvent(_window, 'resize')
        .auditTime(100)
        .map(event => <WindowSize>{width: event['currentTarget'].innerWidth, height: event['currentTarget'].innerHeight})
        .subscribe((windowSize) => {
            this.windowSizeChanged$.next(windowSize);
        });
    }

    readonly windowSizeChanged$ = new BehaviorSubject<WindowSize>(<WindowSize>{width: this._window.innerWidth, height: this._window.innerHeight});
}

Short and sweet and works like a charm.

Answer 14

Before the @Component declaration, you can do that too,

declare var window: any;

The compiler will actually let you then access the global window variable now since you declare it as an assumed global variable with type any.

I wouldn't suggest to access window everywhere in your application though, You should create services that access/modify the needed window attributes (and inject those services in your components) to scope what you can do with the window without letting them to modify the whole window object.

Answer 15

This is the shortest/cleanest answer that I've found working with Angular 4 AOT

Source: https://github.com/angular/angular/issues/12631#issuecomment-274260009

@Injectable()
export class WindowWrapper extends Window {}

export function getWindow() { return window; }

@NgModule({
  ...
  providers: [
    {provide: WindowWrapper, useFactory: getWindow}
  ]
  ...
})
export class AppModule {
  constructor(w: WindowWrapper) {
    console.log(w);
  }
}

Answer 16

Angular 4 introduce InjectToken, and they also create a token for document called DOCUMENT. I think this is the official solution and it works in AoT.

I use the same logic to create a small library called ngx-window-token to prevent doing this over and over.

I have used it in other project and build in AoT without issues.

Here is how I used it in other package

Here is the plunker

In your module

imports: [ BrowserModule, WindowTokenModule ] In your component

constructor(@Inject(WINDOW) _window) { }

Answer 17

To get it to work on Angular 2.1.1 I had to @Inject window using a string

  constructor( @Inject('Window') private window: Window) { }

and then mock it like this

beforeEach(() => {
  let windowMock: Window = <any>{ };
  TestBed.configureTestingModule({
    providers: [
      ApiUriService,
      { provide: 'Window', useFactory: (() => { return windowMock; }) }
    ]
  });

and in the ordinary @NgModule I provide it like this

{ provide: 'Window', useValue: window }

Answer 18

In Angular RC4 the following works which is a combination of some of the above answers, in your root app.ts add it the providers:

@Component({
    templateUrl: 'build/app.html',
    providers: [
        anotherProvider,
        { provide: Window, useValue: window }
    ]
})

Then in your service etc inject it into the constructor

constructor(
      @Inject(Window) private _window: Window,
)

Answer 19

With the release of angular 2.0.0-rc.5 NgModule was introduced. The previous solution stopped working for me. This is what I did to fix it:

app.module.ts:

@NgModule({        
  providers: [
    { provide: 'Window',  useValue: window }
  ],
  declarations: [...],
  imports: [...]
})
export class AppModule {}

In some component:

import { Component, Inject } from '@angular/core';

@Component({...})
export class MyComponent {
    constructor (@Inject('Window') window: Window) {}
}

You could also use an OpaqueToken instead of the string 'Window'

Edit:

The AppModule is used to bootstrap your application in main.ts like this:

import { platformBrowserDynamic  } from '@angular/platform-browser-dynamic';
import { AppModule } from './app/app.module';

platformBrowserDynamic().bootstrapModule(AppModule)

For more information about NgModule read the Angular 2 documentation: https://angular.io/docs/ts/latest/guide/ngmodule.html

Answer 20

I used OpaqueToken for 'Window' string:

import {unimplemented} from '@angular/core/src/facade/exceptions';
import {OpaqueToken, Provider} from '@angular/core/index';

function _window(): any {
    return window;
}

export const WINDOW: OpaqueToken = new OpaqueToken('WindowToken');

export abstract class WindowRef {
    get nativeWindow(): any {
        return unimplemented();
    }
}

export class BrowserWindowRef extends WindowRef {
    constructor() {
        super();
    }
    get nativeWindow(): any {
        return _window();
    }
}


export const WINDOW_PROVIDERS = [
    new Provider(WindowRef, { useClass: BrowserWindowRef }),
    new Provider(WINDOW, { useFactory: _window, deps: [] }),
];

And used just to import WINDOW_PROVIDERS in bootstrap in Angular 2.0.0-rc-4.

But with the release of Angular 2.0.0-rc.5 I need to create a separate module:

import { NgModule } from '@angular/core';
import { WINDOW_PROVIDERS } from './window';

@NgModule({
    providers: [WINDOW_PROVIDERS]
})
export class WindowModule { }

and just defined in the imports property of my main app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';

import { WindowModule } from './other/window.module';

import { AppComponent } from './app.component';

@NgModule({
    imports: [ BrowserModule, WindowModule ],
    declarations: [ ... ],
    providers: [ ... ],
    bootstrap: [ AppComponent ]
})
export class AppModule {}

Answer 21

I know the question is how to inject the window object into a component but you're doing this just to get to localStorage it seems. If you realy just want localStorage, why not use a service that exposes just that, like h5webstorage. Then you component will describe its real dependencies which makes your code more readable.

Answer 22

As of today (April 2016), the code in the previous solution doesn't work, I think it is possible to inject window directly into App.ts and then gather the values you need into a service for global access in the App, but if you prefer to create and inject your own service, a way simpler solution is this.

https://gist.github.com/WilldelaVega777/9afcbd6cc661f4107c2b74dd6090cebf

//--------------------------------------------------------------------------------------------------
// Imports Section:
//--------------------------------------------------------------------------------------------------
import {Injectable} from 'angular2/core'
import {window} from 'angular2/src/facade/browser';

//--------------------------------------------------------------------------------------------------
// Service Class:
//--------------------------------------------------------------------------------------------------
@Injectable()
export class WindowService
{
    //----------------------------------------------------------------------------------------------
    // Constructor Method Section:
    //----------------------------------------------------------------------------------------------
    constructor(){}

    //----------------------------------------------------------------------------------------------
    // Public Properties Section:
    //----------------------------------------------------------------------------------------------
    get nativeWindow() : Window
    {
        return window;
    }
}

Answer 23

You can just inject it after you've set the provider:

import {provide} from 'angular2/core';
bootstrap(..., [provide(Window, {useValue: window})]);

constructor(private window: Window) {
    // this.window
}