code: function mergeMap(project, resultSelector, concurrent) {
      if (concurrent === void 0) {
          concurrent = Number.POSITIVE_INFINITY;
      }
      if (typeof resultSelector === 'function') {
          return function (source) { return source.pipe(mergeMap(function (a, i) { return Object(_observable_from__WEBPACK_IMPORTED_MODULE_4__["from"])(project(a, i)).pipe(Object(_map__WEBPACK_IMPORTED_MODULE_3__["map"])(function (b, ii) { return resultSelector(a, b, i, ii); })); }, concurrent)); };
      }
      else if (typeof resultSelector === 'number') {
          concurrent = resultSelector;
      }
      return function (source) { return source.lift(new MergeMapOperator(project, concurrent)); };
  }
docs: PURE_IMPORTS_START tslib,_util_subscribeToResult,_OuterSubscriber,_map,_observable_from PURE_IMPORTS_END