Exploring the capabilities of accessing observables within RxJS ForkJoin

Question

Exploring the capabilities of accessing observables within RxJS ForkJoin

I have a series of observables that I am combining using the forkJoin operation. I am trying to determine how to identify which observable corresponds to each object in the responses array.

let observables = ... // an array of observables
forkJoin(observables).subscribe(responses=>{
  responses.forEach(response=>{
    // need to determine the source observable for this response
  });
});

I am looking to access specific request parameters after receiving the http response. Unfortunately, I cannot modify the server's response to include additional attributes. Do you have any suggestions on how I can retrieve the original request object after subscribing to the response?

angular typescript rxjs observable

Answer 1

Answer №1

If you want to explore another approach, consider the following code snippets.

let sources = [of(1), of(2), of(3)];

forkJoin(sources)
    .subscribe(
        ([data1, data2, data3]) => {
            // data1 => Result from the first observable
            // data2 => Result from the second observable
            // data3 => Result from the third observable
            this.completedLoading = true;
        }
    );

For handling a dynamic array of observables, you can use:

let sources = [of(1), of(2), of(3), of(4)];

forkJoin(sources)
  .subscribe(
    ([...dataArray]) => {
        console.log(dataArray);
    }
  );

Answer 2

If you want to explore another approach, consider the following code snippets.

let sources = [of(1), of(2), of(3)];

forkJoin(sources)
    .subscribe(
        ([data1, data2, data3]) => {
            // data1 => Result from the first observable
            // data2 => Result from the second observable
            // data3 => Result from the third observable
            this.completedLoading = true;
        }
    );

For handling a dynamic array of observables, you can use:

let sources = [of(1), of(2), of(3), of(4)];

forkJoin(sources)
  .subscribe(
    ([...dataArray]) => {
        console.log(dataArray);
    }
  );

Answer 3

Answer №2

const dataStreams = retrieveDataStreams();

mergeStreams(dataStreams).subscribe(results=>{
    results.forEach(result=>{
       //determine the source of this result from the data stream
       console.log(result.identifyingProperty);
    });
});


retrieveDataStreams() {
  return this.http.get('example_url').pipe(map(result => {
    originalResult: response,
    identifyingProperty: ANY_CUSTOM_IDENTIFIER_YOU_CHOOSE
  });
}

Answer 4

const dataStreams = retrieveDataStreams();

mergeStreams(dataStreams).subscribe(results=>{
    results.forEach(result=>{
       //determine the source of this result from the data stream
       console.log(result.identifyingProperty);
    });
});


retrieveDataStreams() {
  return this.http.get('example_url').pipe(map(result => {
    originalResult: response,
    identifyingProperty: ANY_CUSTOM_IDENTIFIER_YOU_CHOOSE
  });
}

Exploring the capabilities of accessing observables within RxJS ForkJoin

Answer №1

Answer №2

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