code: function duplicates(arr, value, breakable) {
      var i = arr.length;
      var dupes = 0;
      while (i--) {
          if (breakable && dupes > 0)
              break;
          if (is_1.isEqual(arr[i], value))
              dupes += 1;
      }
      return dupes;
  }
docs: Duplicates
  Counts the number of duplicates in an array.
  
  @param arr the array to check for duplicates.
  @param value the value to match.
  @param breakable when true allows breaking at first duplicate.