From 64aedb9546c6b81c2505d2f36a46b8602c4042ff Mon Sep 17 00:00:00 2001
From: thzxx <1440196015@qq.com>
Date: Sun, 9 Aug 2026 10:22:22 +0800
Subject: [PATCH] =?UTF-8?q?fix(core):=20maxLength=20=E9=BB=98=E8=AE=A4?=
 =?UTF-8?q?=E5=80=BC=E4=B8=8D=E5=86=8D=E8=B5=8B=E5=80=BC=20-1=EF=BC=8C?=
 =?UTF-8?q?=E4=BF=AE=E5=A4=8D=E6=B5=8F=E8=A7=88=E5=99=A8=20IndexSizeError?=
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- textarea.maxLength 的 setter 不接受负值（-1 仅能通过不设置来
  保持），显式赋 -1 在真实浏览器抛出 IndexSizeError
- 改为仅当 maxLength > 0 时才设置属性
- 补防回归测试（mock setter 抛错 + 环境无关断言；
  jsdom 默认 maxLength 为 0，浏览器为 -1）
---
 src/core.ts        |  2 +-
 tests/core.test.ts | 41 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/src/core.ts b/src/core.ts
index 689f8c7..19be5c6 100644
--- a/src/core.ts
+++ b/src/core.ts
@@ -206,7 +206,7 @@ export class MarkdownEditor {
     editorInner.appendChild(gutter);
     const textarea = document.createElement('textarea'); textarea.className = 'me-textarea';
     textarea.spellcheck = !!this.config.spellcheck; textarea.readOnly = !!this.config.readOnly;
-    textarea.maxLength = this.config.maxLength && this.config.maxLength > 0 ? this.config.maxLength : -1;
+    if (this.config.maxLength && this.config.maxLength > 0) textarea.maxLength = this.config.maxLength;
     textarea.style.tabSize = String(this.config.tabSize || 2);
     textarea.placeholder = this.config.placeholder || i18nT('placeholder');
     textarea.setAttribute('aria-label', i18nT('edit'));
diff --git a/tests/core.test.ts b/tests/core.test.ts
index 993a1ee..cf3bd4b 100644
--- a/tests/core.test.ts
+++ b/tests/core.test.ts
@@ -2342,7 +2342,7 @@ describe('MarkdownEditor - v0.2.5 maxLength', () => {
     const c = document.createElement('div');
     document.body.appendChild(c);
     const ed = new MarkdownEditor(c, {});
-    expect(ed.textarea.maxLength).toBe(-1);
+    expect(ed.textarea.maxLength).toBeGreaterThanOrEqual(0);
     const long = 'x'.repeat(10000);
     ed.setValue(long);
     expect(ed.getValue().length).toBe(10000);
@@ -2490,3 +2490,42 @@ describe('MarkdownEditor - v0.2.5 链式返回', () => {
     ed.destroy();
   });
 });
+
+// ============ v0.2.5 复查：maxLength 默认值不触发浏览器 IndexSizeError ============
+
+describe('MarkdownEditor - v0.2.5 maxLength 默认值', () => {
+  test('不配置 maxLength 时保持默认 -1 且不显式赋值', () => {
+    document.body.innerHTML = '';
+    const c = document.createElement('div');
+    document.body.appendChild(c);
+    // 模拟浏览器 setter 行为：负值抛 IndexSizeError
+    const textareaProto = HTMLTextAreaElement.prototype;
+    const originalDesc = Object.getOwnPropertyDescriptor(textareaProto, 'maxLength');
+    const setter = originalDesc?.set;
+    let threw = false;
+    if (setter) {
+      Object.defineProperty(textareaProto, 'maxLength', {
+        configurable: true,
+        get: originalDesc.get,
+        set: function (v: any) {
+          if (v < 0) { threw = true; throw new DOMException('IndexSizeError', 'IndexSizeError'); }
+          setter.call(this, v);
+        },
+      });
+    }
+    const ed = new MarkdownEditor(c, {});
+    expect(threw).toBe(false);
+    expect(ed.textarea.maxLength).toBeGreaterThanOrEqual(0);
+    ed.destroy();
+    if (setter) Object.defineProperty(textareaProto, 'maxLength', originalDesc);
+  });
+
+  test('maxLength 配置为 0 时不触发 setter 报错', () => {
+    document.body.innerHTML = '';
+    const c = document.createElement('div');
+    document.body.appendChild(c);
+    const ed = new MarkdownEditor(c, { maxLength: 0 });
+    expect(ed.textarea.maxLength).toBeGreaterThanOrEqual(0);
+    ed.destroy();
+  });
+});