From 33ea8b94f97c35e415241234a4f76684473a8fbf Mon Sep 17 00:00:00 2001
From: Hare <kei.hiracchi.0928@gmail.com>
Date: Thu, 9 Jul 2026 00:04:34 +0900
Subject: [PATCH] Fix CodeMirror folding ranges

---
 .../src/lib/codemirror/decodal.js             | 21 +++++++++++--------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/site/decodal-site/src/lib/codemirror/decodal.js b/site/decodal-site/src/lib/codemirror/decodal.js
index b07631d..a4d3a3f 100644
--- a/site/decodal-site/src/lib/codemirror/decodal.js
+++ b/site/decodal-site/src/lib/codemirror/decodal.js
@@ -25,19 +25,22 @@ const parserWithMetadata = parser.configure({
       LetExpression: context => context.column(context.node.from) + context.unit,
     }),
     foldNodeProp.add({
-      Object: foldDelimited('lBrace', 'rBrace'),
-      Array: foldDelimited('lBracket', 'rBracket'),
-      MatchExpression: foldDelimited('lBrace', 'rBrace'),
+      Object: foldDelimited('{', '}'),
+      Array: foldDelimited('[', ']'),
+      MatchExpression: foldDelimited('{', '}'),
     }),
   ],
 });
 
-function foldDelimited(openName, closeName) {
-  return (node) => {
-    const open = node.getChild(openName);
-    const close = node.getChild(closeName);
-    if (!open || !close || open.to >= close.from) return null;
-    return { from: open.to, to: close.from };
+function foldDelimited(open, close) {
+  return (node, state) => {
+    const text = state.doc.sliceString(node.from, node.to);
+    const openIndex = text.indexOf(open);
+    const closeIndex = text.lastIndexOf(close);
+    if (openIndex < 0 || closeIndex <= openIndex) return null;
+    const from = node.from + openIndex + open.length;
+    const to = node.from + closeIndex;
+    return from < to ? { from, to } : null;
   };
 }