CODEWITHSUNDEEP
angularrxjsobservable
A. Gladkiy
A. Gladkiy

Reputation: 3450

Angular 2 delay before send http request

I'm executing some requests in loop for the same API. On server-side I need to check the previous result to make some changes. But I can't see the previous result if requests are more than one in loop.

in component:

this.service.createEmail(...).delay(5000).debounceTime(5000).timeout(5000).subscribe(...);

and in service:

createEmail(...): Observable<Json> {
    return this.http
            .post('url',
              JSON.stringify(model),
              { headers: this.headers })
            .delay(5000).debounceTime(5000).timeout(5000)
            .map((response: Response) => {
                return this.responseService.extractData(response);
            })
            .catch(error => {
                return this.errorService.handleError(error);
            });
        }

didn't help me. Needed imports exist. Just js setInterval helped me.

How can I do delay before http request in other ways?

Upvotes: 3

Views: 6142

Answers (1)

mickaelw
mickaelw

Reputation: 1513

You can use switchMap and timer:

createEmail(...): Observable<Json> {
   return Observable
            .timer(5000)
            .switchMap(() => 
                this.http.post(
                  'url', 
                  JSON.stringify(model),
                  {headers: this.headers}
                )
            )
            .map((response: Response) => {
                return this.responseService.extractData(response);
            })
            .catch(error => {
               return this.errorService.handleError(error);
            });
}

Before the switchMap you can add debounceTime and another rx operator.

I invite you to check the documentation of switchMap to have more information: https://www.learnrxjs.io/operators/transformation/switchmap.html

You can use .delay when you don't want delivered the result of the observable immediately. For example, I use it when I want simulate the delay of the response of the API.

Upvotes: 1

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