Angular HttpClient - Failed to pass params for the response of Blob type

Question

My background API is to generate Excel. But when I set parameter passing in Angular, passing parameters in the console does not work. How do I pass parameters for blob-type requests?

ExportMyTicket():Observable<Blob> {
  let params = new HttpParams();

  //Parameter passing failure;
  params.append('myParam', '111');

  return this.http.get<Blob>(`${this.exportExcelUrl}`,
    { params, responseType: 'blob' as 'json' })
}

I tried to pass the parameters on the front end, but I couldn't pass them, no matter how I set the parameters.

Answer 1

From HttpParams description

This class is immutable; all mutation operations return a new instance.

1. You should reassign to params with the result returned from .append().

2. Remove the as: 'json' from responseType: 'blob'.

ExportMyTicket():Observable<Blob> {
  let params = new HttpParams();

  //Parameter passing failure;
  params = params.append('myParam', '111');

  return this.http.get<Blob>(`${this.exportExcelUrl}`,
    { params: params, responseType: 'blob' })
}