Add the map method to map ScrollState msg values.

Author: Curtis Schlak

CHANGELOG.md

@@ -8,6 +8,12 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.1.0/)
 and this project adheres to
 [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## 3.1.0
+
+### Added 
+
+- The `map` method for `ScrollState msg` values
+
 ## 3.0.0
 
 ### Added 

elm.json

@@ -3,7 +3,7 @@
     "name": "curtissimo/elm-inertial-scroll-detection",
     "summary": "An event-driven state machine to detect inertial scrolling.",
     "license": "BSD-3-Clause",
-    "version": "3.0.0",
+    "version": "3.1.0",
     "exposed-modules": [
         "Curtissimo.IntertialScrollDetector"
     ],

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@curtissimo/elm-inertial-scroll-detection",
-  "version": "3.0.0",
+  "version": "3.1.0",
   "description": "An event-driven state machine to detect inertial scrolling.",
   "devDependencies": {
     "elm-doc-preview": "^6.0.1",

src/Curtissimo/IntertialScrollDetector.elm

@@ -1,6 +1,7 @@
 module Curtissimo.IntertialScrollDetector exposing
     ( onInertialScroll, init, update
     , InertialDirection(..), inertialX, inertialY, stickyX, stickyY, scrollLeft, scrollTop
+    , map
     , Msg, ScrollState
     )
 
@@ -22,6 +23,11 @@ This is the directed state diagram for the inertial scroll detector.
 @docs InertialDirection, inertialX, inertialY, stickyX, stickyY, scrollLeft, scrollTop
 
 
+# Mapping
+
+@docs map
+
+
 # Opaque types
 
 @docs Msg, ScrollState
@@ -228,6 +234,93 @@ init left top toContentMsg =
         }
 
 
+{-| Map a [`ScrollState`](#ScrollState) from one msg type
+to another.
+-}
+map : (msg1 -> msg2) -> ScrollState msg1 -> ScrollState msg2
+map toMsg state =
+    case state of
+        InertialStarted data ->
+            let
+                horizontal =
+                    data.horizontal
+
+                vertical =
+                    data.vertical
+            in
+            InertialStarted
+                { count = data.count
+                , horizontal = horizontal
+                , vertical = vertical
+                , timestamp = data.timestamp
+                , toContentMsg = data.toContentMsg >> toMsg
+                }
+
+        Inertial data ->
+            let
+                horizontal =
+                    data.horizontal
+
+                vertical =
+                    data.vertical
+            in
+            Inertial
+                { count = data.count
+                , horizontal = horizontal
+                , vertical = vertical
+                , timestamp = data.timestamp
+                , toContentMsg = data.toContentMsg >> toMsg
+                }
+
+        Monitoring data ->
+            let
+                horizontal =
+                    data.horizontal
+
+                vertical =
+                    data.vertical
+            in
+            Monitoring
+                { count = data.count
+                , horizontal = horizontal
+                , vertical = vertical
+                , timestamp = data.timestamp
+                , toContentMsg = data.toContentMsg >> toMsg
+                }
+
+        Moved data ->
+            let
+                horizontal =
+                    data.horizontal
+
+                vertical =
+                    data.vertical
+            in
+            Moved
+                { count = data.count
+                , horizontal = horizontal
+                , vertical = vertical
+                , timestamp = data.timestamp
+                , toContentMsg = data.toContentMsg >> toMsg
+                }
+
+        Touched data ->
+            let
+                horizontal =
+                    data.horizontal
+
+                vertical =
+                    data.vertical
+            in
+            Touched
+                { count = data.count
+                , horizontal = horizontal
+                , vertical = vertical
+                , timestamp = data.timestamp
+                , toContentMsg = data.toContentMsg >> toMsg
+                }
+
+
 {-| Adds the following passive event listeners to the scrollable area.
 
   - `scroll` to monitor for scroll events after touch-end