text: "use strict";
  var __extends = (this && this.__extends) || function (d, b) {
      for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
      function __() { this.constructor = d; }
      d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
  };
  var Subscriber_1 = require('../Subscriber');
  var EmptyError_1 = require('../util/EmptyError');
  /**
   * Emits only the first value (or the first value that meets some condition)
   * emitted by the source Observable.
   *
   * <span class="informal">Emits only the first value. Or emits only the first
   * value that passes some test.</span>
   *
   * <img src="./img/first.png" width="100%">
   *
   * If called with no arguments, `first` emits the first value of the source
   * Observable, then completes. If called with a `predicate` function, `first`
   * emits the first value of the source that matches the specified condition. It
   * may also take a `resultSelector` function to produce the output value from
   * the input value, and a `defaultValue` to emit in case the source completes
   * before it is able to emit a valid value. Throws an error if `defaultValue`
   * was not provided and a matching element is not found.
   *
   * @example <caption>Emit only the first click that happens on the DOM</caption>
   * var clicks = Rx.Observable.fromEvent(document, 'click');
   * var result = clicks.first();
   * result.subscribe(x => console.log(x));
   *
   * @example <caption>Emits the first click that happens on a DIV</caption>
   * var clicks = Rx.Observable.fromEvent(document, 'click');
   * var result = clicks.first(ev => ev.target.tagName === 'DIV');
   * result.subscribe(x => console.log(x));
   *
   * @see {@link filter}
   * @see {@link find}
   * @see {@link take}
   *
   * @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
   * callback if the Observable completes before any `next` notification was sent.
   *
   * @param {function(value: T, index: number, source: Observable<T>): boolean} [predicate]
   * An optional function called with each item to test for condition matching.
   * @param {function(value: T, index: number): R} [resultSelector] A function to
   * produce the value on the output Observable based on the values
   * and the indices of the source Observable. The arguments passed to this
   * function are:
   * - `value`: the value that was emitted on the source.
   * - `index`: the "index" of the value from the source.
   * @param {R} [defaultValue] The default value emitted in case no valid value
   * was found on the source.
   * @return {Observable<T|R>} an Observable of the first item that matches the
   * condition.
   * @method first
   * @owner Observable
   */
  function first(predicate, resultSelector, defaultValue) {
      return this.lift(new FirstOperator(predicate, resultSelector, defaultValue, this));
  }
  exports.first = first;
  var FirstOperator = (function () {
      function FirstOperator(predicate, resultSelector, defaultValue, source) {
          this.predicate = predicate;
          this.resultSelector = resultSelector;
          this.defaultValue = defaultValue;
          this.source = source;
      }
      FirstOperator.prototype.call = function (observer, source) {
          return source._subscribe(new FirstSubscriber(observer, this.predicate, this.resultSelector, this.defaultValue, this.source));
      };
      return FirstOperator;
  }());
  /**
   * We need this JSDoc comment for affecting ESDoc.
   * @ignore
   * @extends {Ignored}
   */
  var FirstSubscriber = (function (_super) {
      __extends(FirstSubscriber, _super);
      function FirstSubscriber(destination, predicate, resultSelector, defaultValue, source) {
          _super.call(this, destination);
          this.predicate = predicate;
          this.resultSelector = resultSelector;
          this.defaultValue = defaultValue;
          this.source = source;
          this.index = 0;
          this.hasCompleted = false;
      }
      FirstSubscriber.prototype._next = function (value) {
          var index = this.index++;
          if (this.predicate) {
              this._tryPredicate(value, index);
          }
          else {
              this._emit(value, index);
          }
      };
      FirstSubscriber.prototype._tryPredicate = function (value, index) {
          var result;
          try {
              result = this.predicate(value, index, this.source);
          }
          catch (err) {
              this.destination.error(err);
              return;
          }
          if (result) {
              this._emit(value, index);
          }
      };
      FirstSubscriber.prototype._emit = function (value, index) {
          if (this.resultSelector) {
              this._tryResultSelector(value, index);
              return;
          }
          this._emitFinal(value);
      };
      FirstSubscriber.prototype._tryResultSelector = function (value, index) {
          var result;
          try {
              result = this.resultSelector(value, index);
          }
          catch (err) {
              this.destination.error(err);
              return;
          }
          this._emitFinal(result);
      };
      FirstSubscriber.prototype._emitFinal = function (value) {
          var destination = this.destination;
          destination.next(value);
          destination.complete();
          this.hasCompleted = true;
      };
      FirstSubscriber.prototype._complete = function () {
          var destination = this.destination;
          if (!this.hasCompleted && typeof this.defaultValue !== 'undefined') {
              destination.next(this.defaultValue);
              destination.complete();
          }
          else if (!this.hasCompleted) {
              destination.error(new EmptyError_1.EmptyError);
          }
      };
      return FirstSubscriber;
  }(Subscriber_1.Subscriber));
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