Rxjs How can i print out all the prime number

I want to use Rxjs to print out all the prime number like below but i am stuck in the return value. I try to use every to return a boolean to the filter but when i try to console.log it prints out the boolean instead of the number in the range. How can i get the value from range after mergeMap

import { range, Observable } from 'rxjs';
import { mergeMap, tap, map, every, filter } from 'rxjs/operators';

function findingPrimeNumber(enterNumber): Observable<boolean> {
  const MaxRangeNumber = enterNumber - 2;
  return range(2, MaxRangeNumber).pipe(
    every(numInRange => enterNumber % numInRange != 0)

range(2, 15).pipe(
  tap(x => console.info(x-1)),
  mergeMap((x) => findingPrimeNumber(x).pipe(map(x => x))),
  filter(x => x)