From 13a9da3bc3a47bfd4660fdd9d887a92cd7c33ddd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Elena=20Torr=C3=B3?= <elenatorro@gmail.com>
Date: Fri, 2 Oct 2026 11:22:19 +0200
Subject: [PATCH] :zap: Reduce commit cost when dropping large selections
 (#12032)

Collect children ids into one transient vector and track WASM shape
changes in a JS Map instead of a volatile persistent map.

AI-assisted-by: claude-opus-5-5
---
 common/src/app/common/files/helpers.cljc | 17 +++++++++--------
 frontend/src/app/main/data/changes.cljs  |  4 ++--
 frontend/src/app/render_wasm/shape.cljs  | 12 ++++++++----
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/common/src/app/common/files/helpers.cljc b/common/src/app/common/files/helpers.cljc
index 2c8ff25600..2b83fa75c5 100644
--- a/common/src/app/common/files/helpers.cljc
+++ b/common/src/app/common/files/helpers.cljc
@@ -162,14 +162,15 @@
   ([objects id {:keys [ignore-children-fn]
                 ;;ignore-children-fn should receive a shape and return a boolean
                 :or {ignore-children-fn (constantly false)}}]
-   (letfn [(get-children-ids-rec [id processed]
-             (when-not (contains? processed id)
-               (when-let [shapes (as-> (get objects id) $
-                                   (:shapes $)
-                                   (remove ignore-children-fn $)
-                                   (some-> $ vec))]
-                 (into shapes (mapcat #(get-children-ids-rec % (conj processed id))) shapes))))]
-     (get-children-ids-rec id #{}))))
+   (letfn [(collect [result id processed]
+             (if (contains? processed id)
+               result
+               (let [shapes    (into [] (remove ignore-children-fn) (dm/get-in objects [id :shapes]))
+                     processed (conj processed id)]
+                 (reduce #(collect %1 %2 processed)
+                         (reduce conj! result shapes)
+                         shapes))))]
+     (persistent! (collect (transient []) id #{})))))
 
 (defn get-children-ids-with-self
   [objects id]
diff --git a/frontend/src/app/main/data/changes.cljs b/frontend/src/app/main/data/changes.cljs
index 865779e5dc..bd8afa6ff7 100644
--- a/frontend/src/app/main/data/changes.cljs
+++ b/frontend/src/app/main/data/changes.cljs
@@ -133,14 +133,14 @@
 
         (if (and (not ignore-wasm?) (features/active-feature? state "render-wasm/v1"))
           ;; Update the wasm model
-          (let [shape-changes (volatile! {})
+          (let [shape-changes (js/Map.)
 
                 state
                 (binding [cts/*shape-changes* shape-changes]
                   (update-in state [:files file-id :data] apply-changes))]
 
             (let [objects (dm/get-in state [:files file-id :data :pages-index (:current-page-id state) :objects])]
-              (wasm.shape/process-shape-changes! objects @shape-changes))
+              (wasm.shape/process-shape-changes! objects (es6-iterator-seq (.entries shape-changes))))
 
             state)
 
diff --git a/frontend/src/app/render_wasm/shape.cljs b/frontend/src/app/render_wasm/shape.cljs
index 3d895841c8..d94bd8d070 100644
--- a/frontend/src/app/render_wasm/shape.cljs
+++ b/frontend/src/app/render_wasm/shape.cljs
@@ -348,10 +348,15 @@
 ;; `conj` empty set initialization
 (def conj* (fnil conj (d/ordered-set)))
 
+(defn- track-change!
+  [self k]
+  (when-let [changes shape/*shape-changes*]
+    (let [id (:id self)]
+      (.set changes id (conj* (.get changes id) k)))))
+
 (defn- impl-assoc
   [self k v]
-  (when shape/*shape-changes*
-    (vswap! shape/*shape-changes* update (:id self) conj* k))
+  (track-change! self k)
 
   (case k
     :id
@@ -379,8 +384,7 @@
 
 (defn- impl-dissoc
   [self k]
-  (when shape/*shape-changes*
-    (vswap! shape/*shape-changes* update (:id self) conj* k))
+  (track-change! self k)
 
   (case k
     :id