fix: onCreateMenu and onCreateContextMenu possibly applying mutated c…

…hanges without returning

src/lib/components/modes/JSONEditorRoot.svelte

@@ -34,6 +34,7 @@
   import TreeMode from './treemode/TreeMode.svelte'
   import type { JSONPatchDocument, JSONPath } from 'immutable-json-patch'
   import { isMenuSpace } from '$lib/typeguards.js'
+  import { cloneDeep } from 'lodash-es'
 
   export let content: Content
   export let selection: JSONEditorSelection | null
@@ -112,12 +113,16 @@
       ? modeMenuItems.concat(items) // menu is empty, readOnly mode
       : modeMenuItems.concat(separatorMenuItem, items)
 
-    return onRenderMenu(updatedItems, { mode, modal: insideModal }) || updatedItems
+    const updatedItemsOriginal = cloneDeep(updatedItems) // the user may change updatedItems in the callback
+
+    return onRenderMenu(updatedItems, { mode, modal: insideModal }) || updatedItemsOriginal
   }
 
   let handleRenderContextMenu: OnRenderContextMenuInternal
   $: handleRenderContextMenu = (items: ContextMenuItem[]) => {
-    return onRenderContextMenu(items, { mode, modal: insideModal, selection }) || items
+    const itemsOriginal = cloneDeep(items) // the user may change items in the callback
+
+    return onRenderContextMenu(items, { mode, modal: insideModal, selection }) || itemsOriginal
   }
 
   export function patch(operations: JSONPatchDocument): JSONPatchResult {

src/routes/examples/custom_menu_buttons/+page.svelte

@@ -47,13 +47,10 @@
       className: 'custom-copy-button'
     }
 
-    const space: MenuSpace = {
-      type: 'space'
-    }
-
-    const itemsWithoutSpace = items.slice(0, items.length - 2)
+    const head = items.slice(0, items.length - 1)
+    const tail = items.slice(items.length - 1) // the tail contains space
 
-    return itemsWithoutSpace.concat([separator, customCopyButton, space])
+    return head.concat(separator, customCopyButton, tail)
   }
 </script>