diff --git a/server/middleware/serveFile.js b/server/middleware/serveFile.js
index e305b98..a6eb1bc 100644
--- a/server/middleware/serveFile.js
+++ b/server/middleware/serveFile.js
@@ -78,7 +78,7 @@ function serveFile(req, res, next) {
           // Cache modules for 1 year.
           res
             .set({
-              "Content-Type": contentType,
+              "Content-Type": `${contentType}; charset=utf-8`,
               "Content-Length": Buffer.byteLength(code),
               "Cache-Control": "public, max-age=31536000",
               "Cache-Tag": "file,js-file,js-module"
@@ -91,9 +91,10 @@ function serveFile(req, res, next) {
       const tags = ["file"]
 
       const ext = path.extname(req.filename).substr(1)
-
       if (ext) tags.push(`${ext}-file`)
 
+      if (contentType === "application/javascript") contentType += "; charset=utf-8"
+
       // Cache files for 1 year.
       res.set({
         "Content-Type": contentType,