Fixing pairs documentation

Author: mattpodwysocki

doc/libraries/rx.complete.md

@@ -49,6 +49,7 @@ NuGet Packages:
 - [`ofObjectChanges`](../api/core/operators/ofobjectchanges.md)
 - [`ofWithScheduler`](../api/core/operators/ofwithscheduler.md)
 - [`onErrorResumeNext`](../api/core/operators/onerrorresumenext.md)
+- [`pairs`](../api/core/operators/pairs.md)
 - [`range`](../api/core/operators/range.md)
 - [`repeat`](../api/core/operators/repeat.md)
 - [`return`](../api/core/operators/return.md)

doc/libraries/rx.lite.md

@@ -38,6 +38,7 @@ NuGet Packages:
 - [`never`](../api/core/operators/never.md)
 - [`of`](../api/core/operators/of.md)
 - [`ofWithScheduler`](../api/core/operators/ofwithscheduler.md)
+- [`pairs`](../api/core/operators/pairs.md)
 - [`range`](../api/core/operators/range.md)
 - [`repeat`](../api/core/operators/repeat.md)
 - [`return | returnValue`](../api/core/operators/return.md)

doc/libraries/rx.md

@@ -35,6 +35,7 @@ NuGet Packages:
 - [`of`](../api/core/operators/of.md)
 - [`ofWithScheduler`](../api/core/operators/ofwithscheduler.md)
 - [`onErrorResumeNext`](../api/core/operators/onerrorresumenext.md)
+- [`pairs`](../api/core/operators/pairs.md)
 - [`range`](../api/core/operators/range.md)
 - [`repeat`](../api/core/operators/repeat.md)
 - [`return | returnValue`](../api/core/operators/return.md)

src/core/perf/operators/map2.js

@@ -0,0 +1,54 @@
+  var MapObservable = (function (__super__) {
+    inherits(MapObservable, __super__);
+
+    function MapObservable(source, selector, thisArg) {
+      this.source = source;
+      this.selector = bindCallback(selector, thisArg, 3);
+      __super__.call(this);
+    }
+
+    MapObservable.prototype.internalMap = function (selector, thisArg) {
+      var self = this;
+      return new MapObservable(this.source, function (x, i, o) { return selector.call(this, self.selector(x, i, o), i, o); }, thisArg)
+    };
+
+    MapObservable.prototype.subscribeCore = function (observer) {
+      return this.source.subscribe(onNext(observer, this.selector, this), onError(observer), onCompleted(observer));
+    };
+    
+    function onNext(observer, selector, source) {
+      var i = 0;
+      return function (x) {
+        var result = tryCatch(selector)(x, i++, source);
+        if (result === errorObj) {
+          observer.onError(result.e);
+        } else { 
+          observer.onNext(result); 
+        }
+      }
+    };
+    
+    function onError(observer) {
+      return function (err) { observer.onError(err); };
+    }
+    
+    function onCompleted(observer) {
+      return function () { observer.onCompleted(); };
+    }
+
+    return MapObservable;
+
+  }(ObservableBase));
+
+  /**
+  * Projects each element of an observable sequence into a new form by incorporating the element's index.
+  * @param {Function} selector A transform function to apply to each source element; the second parameter of the function represents the index of the source element.
+  * @param {Any} [thisArg] Object to use as this when executing callback.
+  * @returns {Observable} An observable sequence whose elements are the result of invoking the transform function on each element of source.
+  */
+  observableProto.map = observableProto.select = function (selector, thisArg) {
+    var selectorFn = typeof selector === 'function' ? selector : function () { return selector; };
+    return this instanceof MapObservable ?
+      this.internalMap(selectorFn, thisArg) :
+      new MapObservable(this, selectorFn, thisArg);
+  };