How to return a promise in a nestjs interceptor?

July 21, 2023

I have created a Class implementing NestInterceptor().

As it returns an Observable(), when I have a promise in it, it does not wait the promise to return the data. How should I do that?
Here is my code:

 export class PointsInterceptor implements NestInterceptor {
      intercept(context: ExecutionContext, next: CallHandler): Observable<any> {

var monaddress = context.switchToHttp().getRequest().body
var retour

//Using Promise
geocoder.geocode(monaddress)
.then(function(res) {
    console.log('res: '+ res);
    retour = res[0].latitude;
  
  })
  .catch(function(err) {
    console.log(err);
    retour = err
  })  ;
  return next.handle().pipe(map(retour => ({ retour })))
}
}

return is executed before the geocoder promise.
I tried to put the return on success and error. A warning is rised:

A function whose declared type is neither 'undefined', 'void', nor 'any' must return a value.ts(2355)

PS: As this is a nestJS interceptor, I have to keep the class returning the Observable().

>Solution :

Why don’t you use async/await syntax like below

async intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
  var monaddress = context.switchToHttp().getRequest().body
  var retour

  cost res = await geocoder.geocode(monaddress)
  console.log('res: '+ res);
  retour = res[0].latitude;

  return next.handle().pipe(map(retour => ({ retour })));
}