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Javascript – how to cancel subscription to window.cookieStore.addEventListener('change', ) in angular service

I have created an angular service which can listen to cookie changes by leveraging the CookieStore Api.
My current code looks as follows:

type CookieChangeType = {
    name: string,
    value: string,
    expires: Date,
    domain: string,
}

interface CookieChangeEvent extends Event {
    changed: CookieChangeType[]
}

type CookieStore = {
    addEventListener: Window["addEventListener"]
}

declare global {
    interface Window {
        cookieStore: CookieStore;
        addEventListener(type: String, listener: (this: Window, ev: CookieChangeEvent) => any, useCapture?: boolean): void;
    }
} 

export class CookieConsentCommonsService {
     
    
    subscribeToConsentCookieChange(callback: () => void): void {
            window.cookieStore.addEventListener('change', (event: CookieChangeEvent) => {
                console.log(`Cookie changed: ${change.name} = ${change.value}`);
                callback();            
            });
    }
}

This code works as expected.
On the top of that I would like to be able to cancel the subscription. I have tried to store the subscription for later :

            const sub = window.cookieStore.addEventListener( ...);
            console.log("sub " + sub)

But there is no return from this code and the output message is:

sub undefined

How can I retrieve a reference for created subscription and later on use it to cancel the subscription?

Tags:

2

Answers


  1. 0

    https://developer.mozilla.org/zh-CN/docs/Web/API/EventTarget/removeEventListener

    function handleChange() {
  // ...
}

// sub
window.cookieStore.addEventListener('change', handleChange);
// unsub
window.cookieStore.removeEventListener('change', handleChange);

    or

    const controller = new AbortController();

// sub
window.cookieStore.addEventListener('change', handleChange, { signal: controller.signal });
// unsub
controller.abort();

    ts

    // Cookie interface definition
interface Cookie {
  name: string;
  value: string;
  expires?: Date | null; // Optional expiration time
  path?: string; // Optional path
  domain?: string; // Optional domain
  secure?: boolean; // Optional secure flag
  sameSite?: 'lax' | 'strict' | 'none'; // Optional SameSite attribute
}

// CookieStore interface inheriting from EventTarget
interface CookieStore extends EventTarget {
  get(name: string): Promise<Cookie | null>;
  getAll(): Promise<Cookie[]>;
  set(cookie: Cookie): Promise<void>;
  delete(name: string): Promise<void>;
}

// Adding CookieStore to the global window object
declare global {
  interface Window {
    cookieStore: CookieStore;
  }
}
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  2. 0

    You can try the rxjs way of handling events using fromEvent, I use takeUntilDestroyed to destroy the observable stream when the component is destroyed.

    cookieStore = (window as any)['cookieStore'];
listener = (callback: () => void, event: any) => {};
destroy$ = inject(DestroyRef);
ngOnInit() {
  this.subscribeToConsentCookieChange(() => {});
}

async subscribeToConsentCookieChange(callback: () => void) {
  fromEvent<any>(this.cookieStore, 'change')
    .pipe(takeUntilDestroyed(this.destroy$))
    .subscribe((event: any) => {
      console.log(`Cookie changed: `, event);
      callback();
    });
  // this.cookieStore.addEventListener('change', (event: any) => {
  //   console.log(`Cookie changed`);
  //   callback();
  // });
  await this.cookieStore.set('test', 'asdf');
}
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