diff --git a/actix-files/CHANGES.md b/actix-files/CHANGES.md
index 12b70c13..bd4030e6 100644
--- a/actix-files/CHANGES.md
+++ b/actix-files/CHANGES.md
@@ -4,10 +4,12 @@
 * `NamedFile` now implements `ServiceFactory` and `HttpServiceFactory` making it much more useful in routing. For example, it can be used directly as a default service. [#2135]
 * For symbolic links, `Content-Disposition` header no longer shows the filename of the original file. [#2156]
 * `Files::redirect_to_slash_directory()` now works as expected when used with `Files::show_files_listing()`. [#2225]
+* `application/{javascript, json, wasm}` mime type now have `inline` disposition by default. [#2257]
 
 [#2135]: https://github.com/actix/actix-web/pull/2135
 [#2156]: https://github.com/actix/actix-web/pull/2156
 [#2225]: https://github.com/actix/actix-web/pull/2225
+[#2257]: https://github.com/actix/actix-web/pull/2257
 
 
 ## 0.6.0-beta.4 - 2021-04-02
diff --git a/actix-files/src/lib.rs b/actix-files/src/lib.rs
index aa5960b5..48d3c49f 100644
--- a/actix-files/src/lib.rs
+++ b/actix-files/src/lib.rs
@@ -279,6 +279,22 @@ mod tests {
         );
     }
 
+    #[actix_rt::test]
+    async fn test_named_file_javascript() {
+        let file = NamedFile::open("tests/test.js").unwrap();
+
+        let req = TestRequest::default().to_http_request();
+        let resp = file.respond_to(&req).await.unwrap();
+        assert_eq!(
+            resp.headers().get(header::CONTENT_TYPE).unwrap(),
+            "application/javascript"
+        );
+        assert_eq!(
+            resp.headers().get(header::CONTENT_DISPOSITION).unwrap(),
+            "inline; filename=\"test.js\""
+        );
+    }
+
     #[actix_rt::test]
     async fn test_named_file_image_attachment() {
         let cd = ContentDisposition {
diff --git a/actix-files/src/named.rs b/actix-files/src/named.rs
index 2183eab5..37f8def3 100644
--- a/actix-files/src/named.rs
+++ b/actix-files/src/named.rs
@@ -120,6 +120,11 @@ impl NamedFile {
 
             let disposition = match ct.type_() {
                 mime::IMAGE | mime::TEXT | mime::VIDEO => DispositionType::Inline,
+                mime::APPLICATION => match ct.subtype() {
+                    mime::JAVASCRIPT | mime::JSON => DispositionType::Inline,
+                    name if name == "wasm" => DispositionType::Inline,
+                    _ => DispositionType::Attachment,
+                },
                 _ => DispositionType::Attachment,
             };
 
@@ -213,9 +218,11 @@ impl NamedFile {
 
     /// Set the Content-Disposition for serving this file. This allows
     /// changing the inline/attachment disposition as well as the filename
-    /// sent to the peer. By default the disposition is `inline` for text,
-    /// image, and video content types, and `attachment` otherwise, and
-    /// the filename is taken from the path provided in the `open` method
+    /// sent to the peer.
+    ///
+    /// By default the disposition is `inline` for `text/*`, `image/*`, `video/*` and
+    /// `application/{javascript, json, wasm}` mime types, and `attachment` otherwise,
+    /// and the filename is taken from the path provided in the `open` method
     /// after converting it to UTF-8 using.
     /// [`std::ffi::OsStr::to_string_lossy`]
     #[inline]
diff --git a/actix-files/tests/test.js b/actix-files/tests/test.js
new file mode 100644
index 00000000..2ee13556
--- /dev/null
+++ b/actix-files/tests/test.js
@@ -0,0 +1 @@
+// this file is empty.