fix: sanitize dynamic attr variable names for aria/data attributes

Hyphens in attribute names like :aria-required produced invalid JS
variable names in generated render functions. Now replaced with
underscores in the temp variable while preserving the HTML attr name.

Author: vojtaholik

packages/core/src/template-compiler.ts

@@ -255,9 +255,10 @@ function compileElement(element: Element, indent: number): string {
         continue;
       }
       // Conditionally render attribute only if value is truthy
-      code += `${pad}const _${attrName}Val = ${attr.value};\n`;
-      code += `${pad}if (_${attrName}Val) {\n`;
-      code += `${pad}  out += " ${attrName}=\\"" + escapeAttr(_${attrName}Val) + "\\"";\n`;
+      const varName = attrName.replace(/[^a-zA-Z0-9_]/g, "_");
+      code += `${pad}const _${varName}Val = ${attr.value};\n`;
+      code += `${pad}if (_${varName}Val) {\n`;
+      code += `${pad}  out += " ${attrName}=\\"" + escapeAttr(_${varName}Val) + "\\"";\n`;
       code += `${pad}}\n`;
     }
   }

packages/core/test/template-compiler.test.ts

@@ -288,8 +288,8 @@ describe("Template Compiler", () => {
       const template = '<div :data-id="props.id">content</div>';
       const result = compileTemplate(template, "test-block");
 
-      expect(result).toContain("_data-idVal = props.id");
-      expect(result).toContain("escapeAttr(_data-idVal)");
+      expect(result).toContain("_data_idVal = props.id");
+      expect(result).toContain("escapeAttr(_data_idVal)");
     });
   });