diff --git a/package.json b/package.json
index a77b717..97eccc1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "vuepress-plugin-demo-code",
-    "version": "0.4.0",
+    "version": "0.4.1",
     "description": "📝 Demo and code plugin for vuepress",
     "main": "src/index.js",
     "files": [
diff --git a/src/DemoAndCode.vue b/src/DemoAndCode.vue
index 34443ec..548487a 100644
--- a/src/DemoAndCode.vue
+++ b/src/DemoAndCode.vue
@@ -27,7 +27,7 @@
         <div class="code-wrapper" ref="codeWrapper" :style="codeWrapperStyle">
             <div
                 v-html="highlightCode"
-                :class="`language-${language}' extra-class`"
+                :class="`language-${language} extra-class`"
             />
         </div>
     </section>
diff --git a/test/__snapshots__/DemoAndCode.test.js.snap b/test/__snapshots__/DemoAndCode.test.js.snap
index 957b916..5482c41 100644
--- a/test/__snapshots__/DemoAndCode.test.js.snap
+++ b/test/__snapshots__/DemoAndCode.test.js.snap
@@ -72,7 +72,7 @@ exports[`DemoAndCode should be rendered 1`] = `
     style="max-height: 200px;"
   >
     <div
-      class="language-vue' extra-class"
+      class="language-vue extra-class"
     >
       <pre
         class="language-vue"