Angular reset TransferState data on route change

Question

I'm using Angular with server-side rendering and TransferState to transfer http data from server to browser. Here is my code:

getProducts() {
    let products = this.tstate.get(PRODUCT_KEY, null as any);
    if (products) {
        return of(products);
    }

    return this.http.post<any>(config.baseUrl+ 'product', {}).pipe(map(
        data => {
            this.tstate.set(PRODUCT_KEY, data as any);
            return data;
        }
    ))
}

In the first load, I get the data from http request. Then the state is initializing. After that, when the route changes, still transfer state keeps the data, so I can't send the request to get the data. Any idea how to reset transfer state in route changing?

Answer 1

You could listen to router events and unset cached data after navigation

constructor(private router: Router,
//...)
{
  this.router.events.subscribe(evt => {
  if (evt instanceof NavigationEnd)
  {
    this.tstate.remove(PRODUCT_KEY);
  }

}

Or you could stop setting transfer data if you are client side

constructor(@Inject(PLATFORM_ID) private platformId: Object
//...)
{
}

getProducts() {
    let products = this.tstate.get(PRODUCT_KEY, null as any);
    if (products) {
        this.tstate.remove(PRODUCT_KEY);
        return of(products);
    }

    return this.http.post<any>(config.baseUrl+ 'product', {}).pipe(map(
        data => {
            if(!isPlatformBrowser(this.platformId)
            {
                this.tstate.set(PRODUCT_KEY, data as any);
            }

            return data;
        }
    ))
}