text: /** PURE_IMPORTS_START tslib,_Subscriber PURE_IMPORTS_END */
  import * as tslib_1 from "tslib";
  import { Subscriber } from '../Subscriber';
  export function scan(accumulator, seed) {
      var hasSeed = false;
      if (arguments.length >= 2) {
          hasSeed = true;
      }
      return function scanOperatorFunction(source) {
          return source.lift(new ScanOperator(accumulator, seed, hasSeed));
      };
  }
  var ScanOperator = /*@__PURE__*/ (function () {
      function ScanOperator(accumulator, seed, hasSeed) {
          if (hasSeed === void 0) {
              hasSeed = false;
          }
          this.accumulator = accumulator;
          this.seed = seed;
          this.hasSeed = hasSeed;
      }
      ScanOperator.prototype.call = function (subscriber, source) {
          return source.subscribe(new ScanSubscriber(subscriber, this.accumulator, this.seed, this.hasSeed));
      };
      return ScanOperator;
  }());
  var ScanSubscriber = /*@__PURE__*/ (function (_super) {
      tslib_1.__extends(ScanSubscriber, _super);
      function ScanSubscriber(destination, accumulator, _seed, hasSeed) {
          var _this = _super.call(this, destination) || this;
          _this.accumulator = accumulator;
          _this._seed = _seed;
          _this.hasSeed = hasSeed;
          _this.index = 0;
          return _this;
      }
      Object.defineProperty(ScanSubscriber.prototype, "seed", {
          get: function () {
              return this._seed;
          },
          set: function (value) {
              this.hasSeed = true;
              this._seed = value;
          },
          enumerable: true,
          configurable: true
      });
      ScanSubscriber.prototype._next = function (value) {
          if (!this.hasSeed) {
              this.seed = value;
              this.destination.next(value);
          }
          else {
              return this._tryNext(value);
          }
      };
      ScanSubscriber.prototype._tryNext = function (value) {
          var index = this.index++;
          var result;
          try {
              result = this.accumulator(this.seed, value, index);
          }
          catch (err) {
              this.destination.error(err);
          }
          this.seed = result;
          this.destination.next(result);
      };
      return ScanSubscriber;
  }(Subscriber));
  //# sourceMappingURL=scan.js.map
  