diff --git a/lib/compile-vue.js b/lib/compile-vue.js
index 33097c5..3fae656 100644
--- a/lib/compile-vue.js
+++ b/lib/compile-vue.js
@@ -289,7 +289,7 @@ export function compileVue(file, imports, options = {}) {
   let js = code.match(JS_EXP)
   let scss = [...code.matchAll(STYLE_EXP)]
   let html = code.match(HTML_EXP) || ['', '']
-  let linePatch = code.slice(0, js.index).split('\n').length // js起始行数修正
+  let linePatch = code.slice(0, js?.index || 0).split('\n').length // js起始行数修正
 
   let hash = md5(file)
   let scopeId = 'data-' + hash