Return value from subscribe in Ionic

Question

So I want to return a value from a subscribe function like this:

async obtenerListadoClases(categoria) {

  var clasesDB = await this.getClases(categoria)
      .subscribe((data: any) => {
         clasesDB = data.clasesDB // **Want to return this**
         console.log(clasesDB,'clasesDB'); // **Getting Value**
      })

      console.log(clasesDB, 'outside'); // **Not Getting Value**
      return clasesDB;
  }

Also, I want to use this function in another place like this:

 var listaClases = await this.claseServicio.obtenerListadoClases(categoria); // Not getting the correct info
  //  console.log(listaClases , 'listado clases');

What Im doing wrong? Or how can I fix it? Thanks in advance!

Answer 1

You can only subscribe to observables.

The Observable way

getClases(categoria): Observable<any> {
  return new Observable(observer => {
    // logic to return data
    observer.next(data);
    observer.complete()
    // logic when error
    observer.error(error);
  });
}

Return the getClases() function

obtenerListadoClases(categoria): Observable<any>{
  return this.getClases(categoria);
}

Use the function where you want:

this.obtenerListadoClases(categoria)
 .subscribe(
   result => {
     // what you want to do with the result
   },
   error => {
     // what you want to do with the error
   }); 

The Promise way

getClases(categoria): Promise<any> {
  return new Promise((resolve, reject) => {
    // logic to return data
    resolve(data);
    // logic when error
    reject(error);
  });
}

Return the getClases() function

obtenerListadoClases(categoria): Promise<any>{
  return this.getClases(categoria);
}

Use the function where you want:

this.obtenerListadoClases(categoria)
 .then(result => {
   // what you want to do with the result
 })
 .catch(error => {
   // what you want to do with the error
 });