I'm having this problem, I have a ProductService that has a boolean function validateProductsBeforeChanges.

Inside validateProductsBeforeChanges I call a function from another service called OrderService which returns an observable.

Some example code:

validateProductsBeforeChanges(idProduct): Boolean {
     this._orderService.getAll()
         .subscribe(orders => {
               this.orders = orders;
               this.ordersWithCurrentMenu = this.orders.filter(x => 
                                                               x.products.find(y => y.code == idProduct));

               if(this.ordersWithCurrentMenu.length > 0) {
                   return false;
               }
               else {
                   return true;
               }
         });
}

The problem is that vs code throws a syntax error:

A function whose declared type is neither 'void' nor 'any' must return a value

So I tried doing something like this:

validateProductsBeforeChanges(idProduct): Boolean {
     this._orderService.getAll()
         .subscribe(orders => {
              this.orders = orders;
              this.ordersWithCurrentMenu = this.orders.filter(x => x.products.find(y => y.code == idProduct));

              if (this.ordersWithCurrentMenu.length > 0) {
                  return false;
              }
              else {
                  return true;
              }
         });

    return false;
}

But in that case, the last return gets executed before the .subcribe ends and the function always returns false.

Any ideas on how to solve this?

Thank you very much!

1 Answers

1
pixelbits On

Something like this:

validateProductsBeforeChanges(idProduct): Observable<Boolean>{
  return this._orderService.getAll()
  .pipe(
      map(orders => 
       orders.filter(x => x.products.find(y => y.code == idProduct))
             .map(filtered => filtered <= 0)
      )          
   );
}

Use like this:

validateProductsBeforeChanges(id).subscribe(t=> {
     if (t) {
        ...
     }
     else {
       ...
     }
})