From 3a3b5415a748ad75bc133097e9d7b7cfd0d73cb8 Mon Sep 17 00:00:00 2001
From: Michael Bull <mikebull94@gmail.com>
Date: Thu, 1 Nov 2018 11:25:20 +0000
Subject: [PATCH] Return the Result in on{Success,Failure}

This facilitates chaining onSuccess/onFailure calls that may perform
arbitrary side-effects, such as logging.
---
 .../com/github/michaelbull/result/On.kt       | 20 +++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/main/kotlin/com/github/michaelbull/result/On.kt b/src/main/kotlin/com/github/michaelbull/result/On.kt
index 6826a0f..dd44c1e 100644
--- a/src/main/kotlin/com/github/michaelbull/result/On.kt
+++ b/src/main/kotlin/com/github/michaelbull/result/On.kt
@@ -1,11 +1,23 @@
 package com.github.michaelbull.result
 
 /**
- * Invokes a [callback] if this [Result] is [Ok].
+ * Invokes an [action] if this [Result] is [Ok].
  */
-inline infix fun <V, E> Result<V, E>.onSuccess(callback: (V) -> Unit) = mapBoth(callback, {})
+inline infix fun <V, E> Result<V, E>.onSuccess(action: (V) -> Unit): Result<V, E> {
+    if (this is Ok) {
+        action(value)
+    }
+
+    return this
+}
 
 /**
- * Invokes a [callback] if this [Result] is [Err].
+ * Invokes an [action] if this [Result] is [Err].
  */
-inline infix fun <V, E> Result<V, E>.onFailure(callback: (E) -> Unit) = mapBoth({}, callback)
+inline infix fun <V, E> Result<V, E>.onFailure(action: (E) -> Unit): Result<V, E> {
+    if (this is Err) {
+        action(error)
+    }
+
+    return this
+}