From 78746c1195c709882e6008b74483fa0cc9ffdcc6 Mon Sep 17 00:00:00 2001
From: Dillon Kearns <dillon@dillonkearns.com>
Date: Mon, 9 Aug 2021 09:29:57 -0700
Subject: [PATCH] Avoid Dict to List conversions to improve performance.

---
 src/DataSource.elm | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/DataSource.elm b/src/DataSource.elm
index 5b9e7ea6..7f64ab70 100644
--- a/src/DataSource.elm
+++ b/src/DataSource.elm
@@ -481,16 +481,19 @@ It would not work correctly if it chose between two responses that were reduced
 -}
 combineReducedDicts : Dict String WhatToDo -> Dict String WhatToDo -> Dict String WhatToDo
 combineReducedDicts dict1 dict2 =
-    (Dict.toList dict1 ++ Dict.toList dict2)
-        |> fromListDedupe Pages.StaticHttpRequest.merge
+    if Dict.size dict1 > Dict.size dict2 then
+        uniqueInsertAll dict2 dict1
+
+    else
+        uniqueInsertAll dict1 dict2
 
 
-fromListDedupe : (comparable -> a -> a -> a) -> List ( comparable, a ) -> Dict comparable a
-fromListDedupe combineFn xs =
-    List.foldl
-        (\( key, value ) acc -> Dict.Extra.insertDedupe (combineFn key) key value acc)
-        Dict.empty
-        xs
+uniqueInsertAll : Dict String WhatToDo -> Dict String WhatToDo -> Dict String WhatToDo
+uniqueInsertAll dictToDedupeMerge startingDict =
+    Dict.foldl
+        (\key value acc -> Dict.Extra.insertDedupe (Pages.StaticHttpRequest.merge key) key value acc)
+        startingDict
+        dictToDedupeMerge
 
 
 lookup : KeepOrDiscard -> ApplicationType -> DataSource value -> RequestsAndPending -> Result Pages.StaticHttpRequest.Error ( Dict String WhatToDo, value )