Prevent TypeError: Attempted to assign to readonly property.

Signed-off-by: Diego Casorran <[email protected]>

dist/perfect-scrollbar.js

@@ -1,6 +1,6 @@
 /*!
- * perfect-scrollbar v1.5.6 - mega.nz build.
- * Copyright 2023 Hyunje Jun, MDBootstrap and Contributors
+ * perfect-scrollbar v1.5.7 - mega.nz build.
+ * Copyright 2024 Hyunje Jun, MDBootstrap and Contributors
  * Licensed under MIT
  */
 
@@ -576,11 +576,10 @@
     let scrollBy = null;
 
     function mouseMoveHandler(e) {
-      if (e.touches && e.touches[0]) {
-        e[pageY] = e.touches[0].pageY;
-      }
+      const y = e.touches && e.touches[0] ? e.touches[0].pageY : e[pageY];
+
       element[scrollTop] =
-        startingScrollTop + scrollBy * (e[pageY] - startingMousePageY);
+        startingScrollTop + scrollBy * (y - startingMousePageY);
       addScrollingClass(i, y);
       updateGeometry(i);
 
@@ -601,10 +600,9 @@
         return;
       }
       startingScrollTop = element[scrollTop];
-      if (touchMode && e.touches) {
-        e[pageY] = e.touches[0].pageY;
-      }
-      startingMousePageY = e[pageY];
+      startingMousePageY =
+        touchMode && e.touches && e.touches[0] ? e.touches[0].pageY : e[pageY];
+
       scrollBy =
         (i[contentHeight] - i[containerHeight]) /
         (i[railYHeight] - i[scrollbarYHeight]);

package.json

@@ -1,6 +1,6 @@
 {
   "name": "perfect-scrollbar",
-  "version": "1.5.6",
+  "version": "1.5.7",
   "description": "Minimalistic but perfect custom scrollbar plugin",
   "author": "Hyunje Jun <[email protected]>",
   "keywords": [
@@ -29,8 +29,8 @@
     "@rollup/plugin-babel": "6.0.4",
     "@rollup/plugin-buble": "1.0.3",
     "chokidar-cli": "3.0.0",
-    "prettier": "3.1.1",
-    "rollup": "4.9.1"
+    "prettier": "3.2.2",
+    "rollup": "4.9.5"
   },
   "scripts": {
     "test": "npm run format:lint && npm run build",

src/handlers/drag-thumb.js

@@ -53,11 +53,10 @@ function bindMouseScrollHandler(
   let scrollBy = null;
 
   function mouseMoveHandler(e) {
-    if (e.touches && e.touches[0]) {
-      e[pageY] = e.touches[0].pageY;
-    }
+    const y = e.touches && e.touches[0] ? e.touches[0].pageY : e[pageY];
+
     element[scrollTop] =
-      startingScrollTop + scrollBy * (e[pageY] - startingMousePageY);
+      startingScrollTop + scrollBy * (y - startingMousePageY);
     addScrollingClass(i, y);
     updateGeometry(i);
 
@@ -78,10 +77,9 @@ function bindMouseScrollHandler(
       return;
     }
     startingScrollTop = element[scrollTop];
-    if (touchMode && e.touches) {
-      e[pageY] = e.touches[0].pageY;
-    }
-    startingMousePageY = e[pageY];
+    startingMousePageY =
+      touchMode && e.touches && e.touches[0] ? e.touches[0].pageY : e[pageY];
+
     scrollBy =
       (i[contentHeight] - i[containerHeight]) /
       (i[railYHeight] - i[scrollbarYHeight]);