From 0e9be4980dda46ef6fc517fd3ac382410849856d Mon Sep 17 00:00:00 2001
From: Thane Gill <me@thanegill.com>
Date: Mon, 11 Jan 2016 17:21:17 -0800
Subject: [PATCH] Add doOn shortcut operators

---
 RxSwift/Observables/Observable+Single.swift | 36 +++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/RxSwift/Observables/Observable+Single.swift b/RxSwift/Observables/Observable+Single.swift
index ac45efa9..41fb76f7 100644
--- a/RxSwift/Observables/Observable+Single.swift
+++ b/RxSwift/Observables/Observable+Single.swift
@@ -113,6 +113,42 @@ extension ObservableType {
             }
         }
     }
+
+    /**
+     Invokes an action for each Next event in the observable sequence, and propagates all observer messages through the result sequence.
+
+     - parameter onNext: Action to invoke for each element in the observable sequence.
+     - returns: The source sequence with the side-effecting behavior applied.
+     */
+    @warn_unused_result(message="http://git.io/rxs.uo")
+    public func doOnNext(onNext: (E throws -> Void))
+        -> Observable<E> {
+        return self.doOn(onNext: onNext)
+    }
+
+    /**
+     Invokes an action for the Error event in the observable sequence, and propagates all observer messages through the result sequence.
+
+     - parameter onError: Action to invoke upon errored termination of the observable sequence.
+     - returns: The source sequence with the side-effecting behavior applied.
+     */
+    @warn_unused_result(message="http://git.io/rxs.uo")
+    public func doOnError(onError: (ErrorType throws -> Void))
+        -> Observable<E> {
+        return self.doOn(onError: onError)
+    }
+
+    /**
+     Invokes an action for the Completed event in the observable sequence, and propagates all observer messages through the result sequence.
+
+     - parameter onCompleted: Action to invoke upon graceful termination of the observable sequence.
+     - returns: The source sequence with the side-effecting behavior applied.
+     */
+    @warn_unused_result(message="http://git.io/rxs.uo")
+    public func doOnComplete(onCompleted: (() throws -> Void))
+        -> Observable<E> {
+        return self.doOn(onCompleted: onCompleted)
+    }
 }
 
 // MARK: startWith