diff --git a/vite.config.ts b/vite.config.ts
index ec53aa91a..ab783999c 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -51,10 +51,11 @@ export default defineConfig(({ command, mode }) => ({
           if (['@traptitech/traq/', 'axios'].some(t => id.includes(t))) {
             return 'apis'
           }
-          if (id.includes('node_modules/highlight.js')) {
+          const hljsLangs = 'node_modules/highlight.js/lib/languages/'
+          const hljsLangIndex = id.indexOf(hljsLangs)
+          if (id.includes(hljsLangs)) {
             // hljsは適当に二つに分割する
-            const t = 'node_modules/highlight.js/lib/languages/'
-            const firstLetter = id.slice(id.indexOf(t) + t.length)[0]
+            const firstLetter = id.slice(hljsLangIndex + hljsLangs.length)[0]
             if (firstLetter < 'i') {
               return 'hljs'
             }