What is the best way to extract accurate information from an observable?

Question

What is the best way to extract accurate information from an observable?

I'm having trouble retrieving the correct data from an observable in my project. Here is the code for my API call:

    getLastxScans(amount: number): Observable<Scan[]> {
    return this.http.get<Scan[]>(`${this.ROOT_URL}/Scan/amount/${amount}`);
  }

When I subscribe to the above call, it returns:

{scans: Array(30)}

However, when I try to store this data in a Scan[] array, it doesn't work as expected. Do I need to access the nested data inside the object? If so, how can I achieve this? Here are the two ways I have tried:

    this.deviceService.getLastxScans(this.scanAmount)
      .subscribe(scans => this.scans = scans);

And also tried:

this.deviceService.getLastxScans(this.scanAmount)
    .subscribe(res => this.scans = res.scans);

angular typescript rxjs observable

Answer 1

Answer №1

When accessing the array as the value of the scans key in the response, you can utilize the following:

this.deviceService.getLastxScans(this.scanAmount)
    .subscribe(res => this.scans = res.scans);

An alternative approach suggested in the comments is:

getLastxScans(amount: number): Observable<Scan[]> {
   return this.http.get<Scan[]>(`${this.ROOT_URL}/Scan/amount/${amount}`)
              .pipe(
                 map((res:any) => res.scans)
              );
}

Answer 2

When accessing the array as the value of the scans key in the response, you can utilize the following:

this.deviceService.getLastxScans(this.scanAmount)
    .subscribe(res => this.scans = res.scans);

An alternative approach suggested in the comments is:

getLastxScans(amount: number): Observable<Scan[]> {
   return this.http.get<Scan[]>(`${this.ROOT_URL}/Scan/amount/${amount}`)
              .pipe(
                 map((res:any) => res.scans)
              );
}

What is the best way to extract accurate information from an observable?

Answer №1

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