I dont get rxjs 6 with angular 6 with interval, switchMap, and map

问题

I want to update my rxjs code to 6 got I don't get it.

Before I had the below that wouth poll for new data every 5 seconds:

import { Observable, interval } from 'rxjs';
import { switchMap, map } from 'rxjs/operators';

var result = interval(5000).switchMap(() => this._authHttp.get(url)).map(res => res.json().results);

Now...of course, it's broken and the documentation leaves me nowhere to go.

How do I write the above to conform to rxjs 6?

Thanks

回答1:

The code should be something like the following. You need to use the pipe operator.

import { interval } from 'rxjs';
import { switchMap, map } from 'rxjs/operators';

const result = interval(5000).pipe(
switchMap(() => this._authHttp.get(url)),    
map(res => res.results)
)

回答2:

After lot of research I could came up with the following updated approach from RxJs' 6 with Angular 6.

The search API is called after each interval of 5 sec and unsubscribed once the count > 5 :

let inter=interval(5000)

let model : ModelComponent;
model=new ModelComponent();
model.emailAddress="mdshahabaz.khan@gmail.com";


let count=1;
this.subscriber=inter.pipe(
          startWith(0),
          switchMap(()=>this.asyncService.makeRequest('search',model))
        ).subscribe(response => {
          console.log("polling")
          console.log(response.list)
          count+=1;
          if(count > 5){
            this.subscriber.unsubscribe();
          }
        });

API request :

   makeRequest(method, body) : Observable<any> {
    const url = this.baseurl + "/" + method;

    const headers = new Headers();
    this.token="Bearer"+" "+localStorage.getItem('token'); 
    headers.append('Authorization', this.token);
    headers.append('Content-Type','application/json');

    const options = new RequestOptions({headers: headers});
    return this.http.post(url, body, options).pipe(
        map((response : Response) => {
            var json = response.json();                

           return json; 
        })
    );
}

Dont forget to unsubscribe to avoid memory leak.

ngOnDestroy(): void {
if(this.subscriber){
  this.subscriber.unsubscribe();
}

}

来源：https://stackoverflow.com/questions/50200859/i-dont-get-rxjs-6-with-angular-6-with-interval-switchmap-and-map

标签

angular

rxjs

rxjs6