feat: 优化代码节点 main 编写体验

- 更新代码节点帮助、占位示例与补全片段

- 保留 _result 旧版兼容提示并补充补全测试

easyflow-ui-admin/packages/tinyflow-ui/src/components/nodes/CodeNode.svelte

@@ -22,22 +22,25 @@
     let currentNode = useNodesData(currentNodeId);
     const { addParameter } = useAddParameter();
     const { updateNodeData } = useSvelteFlow();
-    const codeNodeHelp = `结果如何返回
-- 请把代码执行结果写到 _result 中。
-- JS：_result.answer = 'ok'
-- Python：_result['answer'] = 'ok'
+    const codeNodeHelp = `JavaScript 如何返回结果
+- 定义 main 函数并返回对象，系统会自动执行。
+- main 接收由输入参数组成的对象。
 
 输出参数如何配置
 - 在“输出参数”中新增字段（如 answer、score）。
-- 字段名建议与 _result 的 key 保持一致，便于下游节点引用。
+- 字段名与 main 返回对象的 key 保持一致。
 - 下游节点可引用：代码节点ID.输出参数名。
 
 示例
 - 代码里写：
-  _result.answer = '你好';
-  _result.score = 95;
+  function main({ input }) {
+    return { answer: input, score: 95 };
+  }
 - 输出参数配置：answer(String)、score(Number)
-- 结束节点输出参数可引用：代码节点ID.answer、代码节点ID.score`;
+- 结束节点输出参数可引用：代码节点ID.answer、代码节点ID.score
+
+兼容说明
+- 历史 JavaScript、Python 的 _result 写法仍然支持。`;
 
     const editorParameters = $derived.by(() => {
         return (currentNode?.current?.data?.parameters as Array<any>) || data.parameters || [];
@@ -115,7 +118,7 @@
         <CodeScriptEditor
                   mode="textarea"
                   rows={10}
-                  placeholder="请输入执行代码，注：输出内容需添加到_result中，如：_result['key'] = value 或者 _result.key = value"
+                  placeholder={'请输入代码，例如：function main({ input }) { return { output: input }; }'}
                   style="width: 100%"
                   engine={(data.engine as string) || (defaultEngine as string)}
                   parameters={editorParameters}

easyflow-ui-admin/packages/tinyflow-ui/src/components/utils/codeCompletion.test.ts

@@ -52,6 +52,25 @@ describe('codeCompletion utils', () => {
     ).toBe(true);
   });
 
+  it('should prefer main return snippets for javascript output', () => {
+    const completions = createBusinessCompletions('javascript', []);
+    const mainCompletion = completions.find((item) => item.label === 'main');
+    const resultCompletion = completions.find(
+      (item) => item.label === 'result-object',
+    );
+
+    expect(mainCompletion).toMatchObject({
+      type: 'snippet',
+      detail: '代码节点入口',
+      boost: 1000,
+    });
+    expect(String(mainCompletion?.apply)).toContain('function main');
+    expect(String(mainCompletion?.apply)).toContain('return {');
+    expect(String(resultCompletion?.apply)).toBe(
+      "return { message: 'ok', data };",
+    );
+  });
+
   it('should detect blocked nodes for comment/string/property contexts', () => {
     expect(shouldSkipBusinessCompletion('Comment')).toBe(true);
     expect(shouldSkipBusinessCompletion('LineComment')).toBe(true);

easyflow-ui-admin/packages/tinyflow-ui/src/components/utils/codeCompletion.ts

@@ -30,21 +30,28 @@ const BLOCKED_NODE_NAMES = new Set([
 ]);
 
 const JS_SNIPPETS: Array<{ label: string; insert: string; detail: string }> = [
+  {
+    label: 'main',
+    detail: '代码节点入口',
+    insert:
+      'function main({ input }) {\n  return {\n    output: input,\n  };\n}',
+  },
   {
     label: 'if-else',
     detail: '条件分支',
     insert:
-      'if (condition) {\n  _result.value = value;\n} else {\n  _result.value = null;\n}',
+      'if (condition) {\n  return { value };\n}\nreturn { value: null };',
   },
   {
     label: 'for-of',
     detail: '遍历数组',
-    insert: 'for (const item of items) {\n  // TODO\n}\n_result.done = true;',
+    insert:
+      'const result = [];\nfor (const item of items) {\n  result.push(item);\n}\nreturn { result };',
   },
   {
     label: 'result-object',
     detail: '返回对象',
-    insert: "_result.message = 'ok';\n_result.data = data;",
+    insert: "return { message: 'ok', data };",
   },
 ];
 
@@ -99,7 +106,7 @@ export function createBusinessCompletions(
   const resultCompletion: Completion = {
     label: '_result',
     type: 'variable',
-    detail: '代码节点输出对象',
+    detail: '兼容旧版输出对象',
     boost: 900,
   };
 
@@ -118,7 +125,7 @@ export function createBusinessCompletions(
     type: 'snippet',
     detail: snippet.detail,
     apply: snippet.insert,
-    boost: 500,
+    boost: snippet.label === 'main' ? 1000 : 500,
   }));
 
   return dedupeCompletions([