如何使函数返回 Observable？

Question

I am new to rxjs library and struggle with some things related to the library.

I have function:

  initData(code)
  {  
    this.selectedLot = this.lots.find(x => x.id == code.Id);
    
    this.dataService.getplan(code.Id)
      .subscribe(response => {
        this.plans = response.results;
        this.selectedPlan = this.plans.find(x => x.id == code.homeId);

      }) 
  }

As you can see the function contains service which makes http call and some selection by id from collection. The function initData needs to return Observable.

My question is how can I change the function above that it will return Observable?

Update

I might have multiple http requests in initData function:

  initData(code)
  {  
    this.selectedLot = this.lots.find(x => x.id == code.Id);
    
    this.dataService.getplan(code.Id)
      .subscribe(response => {
        this.plans = response.results;
        this.selectedPlan = this.plans.find(x => x.id == code.homeId);
      }) 
       
       
       this.userService.getUserData(code.userId, code.placeId)
         .subscribe(resp=> { this.user = resp.results[0] });  

       this.userService.getAreaUrl(code.areaId)
         .subscribe(resp=> { this.areaLogoUrl = resp.results[0] });  
  }

Answer 1

Don't subscribe to the observable, instead just return it

 initData(code) {  
    this.selectedLot = this.lots.find(x => x.id == code.Id);
    return this.dataService.getplan(code.Id);
 }

---

If you want to hit api's sequentially (from the comments) make use of concatMap and tap operators.

initData(code) {

   return this.dataService.getplan(code.Id).pipe(
      concatMap(e => this.userService.getUserData(code.userId, code.placeId))
          .pipe(tap(resp => this.user = resp.results[0] )),
      concatMap(e => this.userService.getAreaUrl(code.areaId))
          .pipe(tap(resp => this.areaLogoUrl = resp.results[0] ))
   )

}

Answer 2

You can simply return the Observable . You can use rxjs operators to perform various transformation to the data

 initData(code)
  {  
    this.selectedLot = this.lots.find(x => x.id == code.Id);
    
    return this.dataService.getplan(code.Id).pipe(
      tap(response => {
        this.plans = response.results;
        this.selectedPlan = this.plans.find(x => x.id == code.homeId);

      })
    ) 
  }