diff --git a/packages/vscode/language-server/languagePlugin.ts b/packages/vscode/language-server/languagePlugin.ts
index 5144c64ec8..09bfdc6b6a 100644
--- a/packages/vscode/language-server/languagePlugin.ts
+++ b/packages/vscode/language-server/languagePlugin.ts
@@ -30,9 +30,7 @@ function* getEmbeddedCodes(parsed: SlidevMarkdown): Generator<VirtualCode> {
   const lines = parsed.raw.split('\n')
   function lineToPos(line: number) {
     let pos = 0
-    for (let i = 0; i <= line; i++) {
-      if (!lines[i])
-        break
+    for (let i = 0; i <= line && i < lines.length; i++) {
       pos += lines[i].length + 1
     }
     return pos