diff --git a/cli/ast.rs b/cli/ast.rs
index 8469673312..f823fac21c 100644
--- a/cli/ast.rs
+++ b/cli/ast.rs
@@ -1,6 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-use crate::msg::MediaType;
+use crate::media_type::MediaType;
 use deno_core::error::AnyError;
 use deno_core::ModuleSpecifier;
 use std::error::Error;
diff --git a/cli/file_fetcher.rs b/cli/file_fetcher.rs
index c62e3732e6..7dc39be71a 100644
--- a/cli/file_fetcher.rs
+++ b/cli/file_fetcher.rs
@@ -5,7 +5,7 @@ use crate::http_cache::HttpCache;
 use crate::http_util;
 use crate::http_util::create_http_client;
 use crate::http_util::FetchOnceResult;
-use crate::msg;
+use crate::media_type::MediaType;
 use crate::permissions::Permissions;
 use crate::text_encoding;
 use deno_core::error::custom_error;
@@ -79,7 +79,7 @@ pub struct SourceFile {
   pub url: Url,
   pub filename: PathBuf,
   pub types_header: Option<String>,
-  pub media_type: msg::MediaType,
+  pub media_type: MediaType,
   pub source_code: TextDocument,
 }
 
@@ -573,7 +573,7 @@ impl SourceFileFetcher {
 fn map_content_type(
   path: &Path,
   content_type: Option<&str>,
-) -> (msg::MediaType, Option<String>) {
+) -> (MediaType, Option<String>) {
   match content_type {
     Some(content_type) => {
       // Sometimes there is additional data after the media type in
@@ -587,7 +587,7 @@ fn map_content_type(
         | "video/vnd.dlna.mpeg-tts"
         | "video/mp2t"
         | "application/x-typescript" => {
-          map_js_like_extension(path, msg::MediaType::TypeScript)
+          map_js_like_extension(path, MediaType::TypeScript)
         }
         "application/javascript"
         | "text/javascript"
@@ -595,15 +595,15 @@ fn map_content_type(
         | "text/ecmascript"
         | "application/x-javascript"
         | "application/node" => {
-          map_js_like_extension(path, msg::MediaType::JavaScript)
+          map_js_like_extension(path, MediaType::JavaScript)
         }
-        "application/json" | "text/json" => msg::MediaType::Json,
-        "application/wasm" => msg::MediaType::Wasm,
+        "application/json" | "text/json" => MediaType::Json,
+        "application/wasm" => MediaType::Wasm,
         // Handle plain and possibly webassembly
-        "text/plain" | "application/octet-stream" => msg::MediaType::from(path),
+        "text/plain" | "application/octet-stream" => MediaType::from(path),
         _ => {
           debug!("unknown content type: {}", content_type);
-          msg::MediaType::Unknown
+          MediaType::Unknown
         }
       };
 
@@ -614,20 +614,17 @@ fn map_content_type(
 
       (media_type, charset)
     }
-    None => (msg::MediaType::from(path), None),
+    None => (MediaType::from(path), None),
   }
 }
 
-fn map_js_like_extension(
-  path: &Path,
-  default: msg::MediaType,
-) -> msg::MediaType {
+fn map_js_like_extension(path: &Path, default: MediaType) -> MediaType {
   match path.extension() {
     None => default,
     Some(os_str) => match os_str.to_str() {
       None => default,
-      Some("jsx") => msg::MediaType::JSX,
-      Some("tsx") => msg::MediaType::TSX,
+      Some("jsx") => MediaType::JSX,
+      Some("tsx") => MediaType::TSX,
       Some(_) => default,
     },
   }
@@ -816,7 +813,7 @@ mod tests {
       r.source_code.bytes,
       &b"export { printHello } from \"./print_hello.ts\";\n"[..]
     );
-    assert_eq!(&(r.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(r.media_type), &MediaType::TypeScript);
 
     let mut metadata =
       crate::http_cache::Metadata::read(&cache_filename).unwrap();
@@ -847,7 +844,7 @@ mod tests {
     );
     // If get_source_file does not call remote, this should be JavaScript
     // as we modified before! (we do not overwrite .headers.json due to no http fetch)
-    assert_eq!(&(r2.media_type), &msg::MediaType::JavaScript);
+    assert_eq!(&(r2.media_type), &MediaType::JavaScript);
     let (_, headers) = fetcher_2.http_cache.get(&module_url_1).unwrap();
 
     assert_eq!(
@@ -886,7 +883,7 @@ mod tests {
     );
     // If get_source_file does not call remote, this should be JavaScript
     // as we modified before! (we do not overwrite .headers.json due to no http fetch)
-    assert_eq!(&(r3.media_type), &msg::MediaType::Json);
+    assert_eq!(&(r3.media_type), &MediaType::Json);
     let metadata = crate::http_cache::Metadata::read(&cache_filename).unwrap();
     assert_eq!(
       metadata
@@ -916,7 +913,7 @@ mod tests {
     let expected4 = &b"export { printHello } from \"./print_hello.ts\";\n"[..];
     assert_eq!(r4.source_code.bytes, expected4);
     // Resolved back to TypeScript
-    assert_eq!(&(r4.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(r4.media_type), &MediaType::TypeScript);
   }
 
   #[tokio::test]
@@ -943,7 +940,7 @@ mod tests {
     let r = result.unwrap();
     let expected = b"export const loaded = true;\n";
     assert_eq!(r.source_code.bytes, expected);
-    assert_eq!(&(r.media_type), &msg::MediaType::JavaScript);
+    assert_eq!(&(r.media_type), &MediaType::JavaScript);
     let (_, headers) = fetcher.http_cache.get(&module_url).unwrap();
     assert_eq!(
       headers
@@ -982,7 +979,7 @@ mod tests {
     // If get_source_file does not call remote, this should be TypeScript
     // as we modified before! (we do not overwrite .headers.json due to no http
     // fetch)
-    assert_eq!(&(r2.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(r2.media_type), &MediaType::TypeScript);
     let metadata = crate::http_cache::Metadata::read(&cache_filename).unwrap();
     assert_eq!(
       metadata
@@ -1013,7 +1010,7 @@ mod tests {
     assert_eq!(r3.source_code.bytes, expected3);
     // Now the old .headers.json file should be overwritten back to JavaScript!
     // (due to http fetch)
-    assert_eq!(&(r3.media_type), &msg::MediaType::JavaScript);
+    assert_eq!(&(r3.media_type), &MediaType::JavaScript);
     let (_, headers) = fetcher.http_cache.get(&module_url).unwrap();
     assert_eq!(
       headers
@@ -1429,7 +1426,7 @@ mod tests {
     assert!(result.is_ok());
     let r = result.unwrap();
     assert_eq!(r.source_code.bytes, b"export const loaded = true;\n");
-    assert_eq!(&(r.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(r.media_type), &MediaType::TypeScript);
 
     // Modify .metadata.json, make sure read from local
     let cache_filename = fetcher.http_cache.get_cache_filename(&module_url);
@@ -1448,7 +1445,7 @@ mod tests {
     let r2 = result2.unwrap().unwrap();
     assert_eq!(r2.source_code.bytes, b"export const loaded = true;\n");
     // Not MediaType::TypeScript due to .headers.json modification
-    assert_eq!(&(r2.media_type), &msg::MediaType::JavaScript);
+    assert_eq!(&(r2.media_type), &MediaType::JavaScript);
   }
 
   #[tokio::test]
@@ -1469,7 +1466,7 @@ mod tests {
     assert!(result.is_ok());
     let r = result.unwrap();
     assert_eq!(r.source_code.bytes, b"export const loaded = true;\n");
-    assert_eq!(&(r.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(r.media_type), &MediaType::TypeScript);
     let (_, headers) = fetcher.http_cache.get(module_url).unwrap();
     assert_eq!(
       headers
@@ -1501,7 +1498,7 @@ mod tests {
     assert!(result.is_ok());
     let r2 = result.unwrap();
     assert_eq!(r2.source_code.bytes, b"export const loaded = true;\n");
-    assert_eq!(&(r2.media_type), &msg::MediaType::JavaScript);
+    assert_eq!(&(r2.media_type), &MediaType::JavaScript);
     let (_, headers) = fetcher.http_cache.get(module_url).unwrap();
     assert_eq!(
       headers
@@ -1533,7 +1530,7 @@ mod tests {
     assert!(result.is_ok());
     let r3 = result.unwrap();
     assert_eq!(r3.source_code.bytes, b"export const loaded = true;\n");
-    assert_eq!(&(r3.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(r3.media_type), &MediaType::TypeScript);
     let (_, headers) = fetcher.http_cache.get(module_url).unwrap();
     assert_eq!(
       headers
@@ -1682,43 +1679,43 @@ mod tests {
     // Extension only
     assert_eq!(
       map_content_type(Path::new("foo/bar.ts"), None).0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.tsx"), None).0,
-      msg::MediaType::TSX
+      MediaType::TSX
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.d.ts"), None).0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.js"), None).0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.txt"), None).0,
-      msg::MediaType::Unknown
+      MediaType::Unknown
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.jsx"), None).0,
-      msg::MediaType::JSX
+      MediaType::JSX
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.json"), None).0,
-      msg::MediaType::Json
+      MediaType::Json
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.wasm"), None).0,
-      msg::MediaType::Wasm
+      MediaType::Wasm
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.cjs"), None).0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), None).0,
-      msg::MediaType::Unknown
+      MediaType::Unknown
     );
   }
 
@@ -1727,61 +1724,61 @@ mod tests {
     // Media Type
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("application/typescript")).0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("text/typescript")).0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("video/vnd.dlna.mpeg-tts")).0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("video/mp2t")).0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("application/x-typescript"))
         .0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("application/javascript")).0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("text/javascript")).0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("application/ecmascript")).0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("text/ecmascript")).0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("application/x-javascript"))
         .0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("application/json")).0,
-      msg::MediaType::Json
+      MediaType::Json
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("application/node")).0,
-      msg::MediaType::JavaScript
+      MediaType::JavaScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("text/json")).0,
-      msg::MediaType::Json
+      MediaType::Json
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar"), Some("text/json; charset=utf-8 ")),
-      (msg::MediaType::Json, Some("utf-8".to_owned()))
+      (MediaType::Json, Some("utf-8".to_owned()))
     );
   }
 
@@ -1789,11 +1786,11 @@ mod tests {
   fn test_map_file_extension_media_type_with_extension() {
     assert_eq!(
       map_content_type(Path::new("foo/bar.ts"), Some("text/plain")).0,
-      msg::MediaType::TypeScript
+      MediaType::TypeScript
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.ts"), Some("foo/bar")).0,
-      msg::MediaType::Unknown
+      MediaType::Unknown
     );
     assert_eq!(
       map_content_type(
@@ -1801,7 +1798,7 @@ mod tests {
         Some("application/typescript"),
       )
       .0,
-      msg::MediaType::TSX
+      MediaType::TSX
     );
     assert_eq!(
       map_content_type(
@@ -1809,7 +1806,7 @@ mod tests {
         Some("application/javascript"),
       )
       .0,
-      msg::MediaType::TSX
+      MediaType::TSX
     );
     assert_eq!(
       map_content_type(
@@ -1817,7 +1814,7 @@ mod tests {
         Some("application/x-typescript"),
       )
       .0,
-      msg::MediaType::TSX
+      MediaType::TSX
     );
     assert_eq!(
       map_content_type(
@@ -1825,11 +1822,11 @@ mod tests {
         Some("video/vnd.dlna.mpeg-tts"),
       )
       .0,
-      msg::MediaType::TSX
+      MediaType::TSX
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.tsx"), Some("video/mp2t")).0,
-      msg::MediaType::TSX
+      MediaType::TSX
     );
     assert_eq!(
       map_content_type(
@@ -1837,7 +1834,7 @@ mod tests {
         Some("application/javascript"),
       )
       .0,
-      msg::MediaType::JSX
+      MediaType::JSX
     );
     assert_eq!(
       map_content_type(
@@ -1845,7 +1842,7 @@ mod tests {
         Some("application/x-typescript"),
       )
       .0,
-      msg::MediaType::JSX
+      MediaType::JSX
     );
     assert_eq!(
       map_content_type(
@@ -1853,11 +1850,11 @@ mod tests {
         Some("application/ecmascript"),
       )
       .0,
-      msg::MediaType::JSX
+      MediaType::JSX
     );
     assert_eq!(
       map_content_type(Path::new("foo/bar.jsx"), Some("text/ecmascript")).0,
-      msg::MediaType::JSX
+      MediaType::JSX
     );
     assert_eq!(
       map_content_type(
@@ -1865,7 +1862,7 @@ mod tests {
         Some("application/x-javascript"),
       )
       .0,
-      msg::MediaType::JSX
+      MediaType::JSX
     );
   }
 
@@ -1896,7 +1893,7 @@ mod tests {
     assert!(source.is_ok());
     let source = source.unwrap();
     assert_eq!(source.source_code.bytes, b"console.log('etag')");
-    assert_eq!(&(source.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(source.media_type), &MediaType::TypeScript);
 
     let (_, headers) = fetcher.http_cache.get(&module_url).unwrap();
     assert_eq!(
@@ -1951,7 +1948,7 @@ mod tests {
     assert!(source.is_ok());
     let source = source.unwrap();
     assert_eq!(source.source_code.bytes, b"export const foo = 'foo';");
-    assert_eq!(&(source.media_type), &msg::MediaType::JavaScript);
+    assert_eq!(&(source.media_type), &MediaType::JavaScript);
     assert_eq!(
       source.types_header,
       Some("./xTypeScriptTypes.d.ts".to_string())
@@ -2023,7 +2020,7 @@ mod tests {
     assert_eq!(&source.source_code.charset.to_lowercase()[..], charset);
     let text = &source.source_code.to_str().unwrap();
     assert_eq!(text, expected_content);
-    assert_eq!(&(source.media_type), &msg::MediaType::TypeScript);
+    assert_eq!(&(source.media_type), &MediaType::TypeScript);
 
     let (_, headers) = fetcher.http_cache.get(&module_url).unwrap();
     assert_eq!(
diff --git a/cli/global_state.rs b/cli/global_state.rs
index fa086b721e..700909f8f6 100644
--- a/cli/global_state.rs
+++ b/cli/global_state.rs
@@ -6,10 +6,9 @@ use crate::flags;
 use crate::http_cache;
 use crate::import_map::ImportMap;
 use crate::lockfile::Lockfile;
+use crate::media_type::MediaType;
 use crate::module_graph::ModuleGraphFile;
 use crate::module_graph::ModuleGraphLoader;
-use crate::msg;
-use crate::msg::MediaType;
 use crate::permissions::Permissions;
 use crate::state::exit_unstable;
 use crate::tsc::CompiledModule;
@@ -202,10 +201,8 @@ impl GlobalState {
 
     // Check if we need to compile files
     let was_compiled = match out.media_type {
-      msg::MediaType::TypeScript
-      | msg::MediaType::TSX
-      | msg::MediaType::JSX => true,
-      msg::MediaType::JavaScript => self.ts_compiler.compile_js,
+      MediaType::TypeScript | MediaType::TSX | MediaType::JSX => true,
+      MediaType::JavaScript => self.ts_compiler.compile_js,
       _ => false,
     };
 
@@ -288,10 +285,8 @@ fn needs_compilation(
   module_graph_files: &[&ModuleGraphFile],
 ) -> bool {
   let mut needs_compilation = match media_type {
-    msg::MediaType::TypeScript | msg::MediaType::TSX | msg::MediaType::JSX => {
-      true
-    }
-    msg::MediaType::JavaScript => compile_js,
+    MediaType::TypeScript | MediaType::TSX | MediaType::JSX => true,
+    MediaType::JavaScript => compile_js,
     _ => false,
   };
 
diff --git a/cli/info.rs b/cli/info.rs
index f39e6b4f0a..fdc021eff3 100644
--- a/cli/info.rs
+++ b/cli/info.rs
@@ -1,7 +1,6 @@
 use crate::colors;
 use crate::global_state::GlobalState;
 use crate::module_graph::{ModuleGraph, ModuleGraphFile, ModuleGraphLoader};
-use crate::msg;
 use crate::ModuleSpecifier;
 use crate::Permissions;
 use deno_core::error::AnyError;
@@ -56,7 +55,8 @@ impl ModuleDepInfo {
       .get_source_map_file(&module_specifier)
       .ok()
       .map(|file| file.filename.to_string_lossy().to_string());
-    let file_type = msg::enum_name_media_type(out.media_type).to_string();
+    let file_type =
+      crate::media_type::enum_name_media_type(out.media_type).to_string();
 
     let deps = FileInfoDepTree::new(&module_graph, &module_specifier);
     let dep_count = get_unique_dep_count(&module_graph) - 1;
@@ -350,8 +350,8 @@ pub fn human_size(bytse: f64) -> String {
 mod test {
   use super::*;
   use crate::ast::Location;
+  use crate::media_type::MediaType;
   use crate::module_graph::ImportDescriptor;
-  use crate::MediaType;
 
   #[test]
   fn human_size_test() {
diff --git a/cli/lint.rs b/cli/lint.rs
index 3501705ad5..ba159146ee 100644
--- a/cli/lint.rs
+++ b/cli/lint.rs
@@ -11,7 +11,7 @@ use crate::colors;
 use crate::fmt::collect_files;
 use crate::fmt::run_parallelized;
 use crate::fmt_errors;
-use crate::msg;
+use crate::media_type::MediaType;
 use deno_core::error::generic_error;
 use deno_core::error::AnyError;
 use deno_lint::diagnostic::LintDiagnostic;
@@ -131,7 +131,7 @@ fn lint_file(
 ) -> Result<(Vec<LintDiagnostic>, String), AnyError> {
   let file_name = file_path.to_string_lossy().to_string();
   let source_code = fs::read_to_string(&file_path)?;
-  let media_type = msg::MediaType::from(&file_path);
+  let media_type = MediaType::from(&file_path);
   let syntax = ast::get_syntax(&media_type);
 
   let lint_rules = rules::get_recommended_rules();
@@ -158,7 +158,7 @@ fn lint_stdin(json: bool) -> Result<(), AnyError> {
   };
   let mut reporter = create_reporter(reporter_kind);
   let lint_rules = rules::get_recommended_rules();
-  let syntax = ast::get_syntax(&msg::MediaType::TypeScript);
+  let syntax = ast::get_syntax(&MediaType::TypeScript);
   let mut linter = create_linter(syntax, lint_rules);
   let mut has_error = false;
   let pseudo_file_name = "_stdin.ts";
diff --git a/cli/main.rs b/cli/main.rs
index c67875fe89..a300c3d69a 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -49,9 +49,9 @@ pub mod installer;
 mod js;
 mod lint;
 mod lockfile;
+mod media_type;
 mod metrics;
 mod module_graph;
-pub mod msg;
 mod op_fetch_asset;
 pub mod ops;
 pub mod permissions;
@@ -77,7 +77,7 @@ use crate::file_fetcher::SourceFileFetcher;
 use crate::file_fetcher::TextDocument;
 use crate::fs as deno_fs;
 use crate::global_state::GlobalState;
-use crate::msg::MediaType;
+use crate::media_type::MediaType;
 use crate::permissions::Permissions;
 use crate::worker::MainWorker;
 use deno_core::error::AnyError;
@@ -378,7 +378,7 @@ async fn doc_command(
   let doc_parser = doc::DocParser::new(loader, private);
 
   let parse_result = if source_file == "--builtin" {
-    let syntax = ast::get_syntax(&msg::MediaType::Dts);
+    let syntax = ast::get_syntax(&MediaType::Dts);
     doc_parser.parse_source(
       "lib.deno.d.ts",
       syntax,
diff --git a/cli/msg.rs b/cli/media_type.rs
similarity index 65%
rename from cli/msg.rs
rename to cli/media_type.rs
index 520d46fc2d..84e6fbe8ec 100644
--- a/cli/msg.rs
+++ b/cli/media_type.rs
@@ -117,65 +117,31 @@ pub fn enum_name_media_type(mt: MediaType) -> &'static str {
   }
 }
 
-// Warning! The values in this enum are duplicated in js/compiler.ts
-// Update carefully!
-#[allow(non_camel_case_types)]
-#[repr(i32)]
-#[derive(Clone, Copy, PartialEq, Debug)]
-pub enum CompilerRequestType {
-  Compile = 0,
-  Bundle = 1,
-  RuntimeCompile = 2,
-  RuntimeBundle = 3,
-  RuntimeTranspile = 4,
-}
-
-impl Serialize for CompilerRequestType {
-  fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-  where
-    S: Serializer,
-  {
-    let value: i32 = match self {
-      CompilerRequestType::Compile => 0 as i32,
-      CompilerRequestType::Bundle => 1 as i32,
-      CompilerRequestType::RuntimeCompile => 2 as i32,
-      CompilerRequestType::RuntimeBundle => 3 as i32,
-      CompilerRequestType::RuntimeTranspile => 4 as i32,
-    };
-    Serialize::serialize(&value, serializer)
-  }
-}
-
-#[cfg(test)]
-mod tests {
-  use super::*;
-
-  #[test]
-  fn test_map_file_extension() {
-    assert_eq!(
-      MediaType::from(Path::new("foo/bar.ts")),
-      MediaType::TypeScript
-    );
-    assert_eq!(MediaType::from(Path::new("foo/bar.tsx")), MediaType::TSX);
-    assert_eq!(
-      MediaType::from(Path::new("foo/bar.d.ts")),
-      MediaType::TypeScript
-    );
-    assert_eq!(
-      MediaType::from(Path::new("foo/bar.js")),
-      MediaType::JavaScript
-    );
-    assert_eq!(MediaType::from(Path::new("foo/bar.jsx")), MediaType::JSX);
-    assert_eq!(MediaType::from(Path::new("foo/bar.json")), MediaType::Json);
-    assert_eq!(MediaType::from(Path::new("foo/bar.wasm")), MediaType::Wasm);
-    assert_eq!(
-      MediaType::from(Path::new("foo/bar.cjs")),
-      MediaType::JavaScript
-    );
-    assert_eq!(
-      MediaType::from(Path::new("foo/bar.txt")),
-      MediaType::Unknown
-    );
-    assert_eq!(MediaType::from(Path::new("foo/bar")), MediaType::Unknown);
-  }
+#[test]
+fn test_map_file_extension() {
+  assert_eq!(
+    MediaType::from(Path::new("foo/bar.ts")),
+    MediaType::TypeScript
+  );
+  assert_eq!(MediaType::from(Path::new("foo/bar.tsx")), MediaType::TSX);
+  assert_eq!(
+    MediaType::from(Path::new("foo/bar.d.ts")),
+    MediaType::TypeScript
+  );
+  assert_eq!(
+    MediaType::from(Path::new("foo/bar.js")),
+    MediaType::JavaScript
+  );
+  assert_eq!(MediaType::from(Path::new("foo/bar.jsx")), MediaType::JSX);
+  assert_eq!(MediaType::from(Path::new("foo/bar.json")), MediaType::Json);
+  assert_eq!(MediaType::from(Path::new("foo/bar.wasm")), MediaType::Wasm);
+  assert_eq!(
+    MediaType::from(Path::new("foo/bar.cjs")),
+    MediaType::JavaScript
+  );
+  assert_eq!(
+    MediaType::from(Path::new("foo/bar.txt")),
+    MediaType::Unknown
+  );
+  assert_eq!(MediaType::from(Path::new("foo/bar")), MediaType::Unknown);
 }
diff --git a/cli/module_graph.rs b/cli/module_graph.rs
index 0308e6ebc7..41863762a6 100644
--- a/cli/module_graph.rs
+++ b/cli/module_graph.rs
@@ -5,7 +5,7 @@ use crate::checksum;
 use crate::file_fetcher::SourceFile;
 use crate::file_fetcher::SourceFileFetcher;
 use crate::import_map::ImportMap;
-use crate::msg::MediaType;
+use crate::media_type::MediaType;
 use crate::permissions::Permissions;
 use crate::tsc::pre_process_file;
 use crate::tsc::ImportDesc;
diff --git a/cli/tsc.rs b/cli/tsc.rs
index 888c6fdeb9..570d5f812c 100644
--- a/cli/tsc.rs
+++ b/cli/tsc.rs
@@ -12,10 +12,9 @@ use crate::flags::Flags;
 use crate::fmt_errors::JsError;
 use crate::global_state::GlobalState;
 use crate::js;
+use crate::media_type::MediaType;
 use crate::module_graph::ModuleGraph;
 use crate::module_graph::ModuleGraphLoader;
-use crate::msg;
-use crate::msg::MediaType;
 use crate::ops;
 use crate::permissions::Permissions;
 use crate::source_maps::SourceMapGetter;
@@ -35,6 +34,7 @@ use log::Level;
 use regex::Regex;
 use serde::Deserialize;
 use serde::Serialize;
+use serde::Serializer;
 use serde_json::json;
 use serde_json::Value;
 use sourcemap::SourceMap;
@@ -630,7 +630,7 @@ impl TsCompiler {
     );
 
     let j = json!({
-      "type": msg::CompilerRequestType::Compile,
+      "type": CompilerRequestType::Compile,
       "target": target,
       "rootNames": root_names,
       "performance": performance,
@@ -751,7 +751,7 @@ impl TsCompiler {
     );
 
     let j = json!({
-      "type": msg::CompilerRequestType::Bundle,
+      "type": CompilerRequestType::Bundle,
       "target": target,
       "rootNames": root_names,
       "performance": performance,
@@ -899,9 +899,7 @@ impl TsCompiler {
 
       // NOTE: JavaScript files are only cached to disk if `checkJs`
       // option in on
-      if source_file.media_type == msg::MediaType::JavaScript
-        && !self.compile_js
-      {
+      if source_file.media_type == MediaType::JavaScript && !self.compile_js {
         continue;
       }
 
@@ -948,7 +946,7 @@ impl TsCompiler {
     let compiled_module = SourceFile {
       url: module_url.clone(),
       filename: compiled_code_filename,
-      media_type: msg::MediaType::JavaScript,
+      media_type: MediaType::JavaScript,
       source_code: compiled_code.into(),
       types_header: None,
     };
@@ -1005,7 +1003,7 @@ impl TsCompiler {
     let source_map_file = SourceFile {
       url: module_specifier.as_url().to_owned(),
       filename: source_map_filename,
-      media_type: msg::MediaType::JavaScript,
+      media_type: MediaType::JavaScript,
       source_code: source_code.into(),
       types_header: None,
     };
@@ -1268,7 +1266,7 @@ pub async fn runtime_compile(
     serde_json::to_value(module_graph).expect("Failed to serialize data");
 
   let req_msg = json!({
-    "type": msg::CompilerRequestType::RuntimeCompile,
+    "type": CompilerRequestType::RuntimeCompile,
     "target": "runtime",
     "rootNames": root_names,
     "sourceFileMap": module_graph_json,
@@ -1379,7 +1377,7 @@ pub async fn runtime_bundle(
   tsc_config::json_merge(&mut compiler_options, &bundler_options);
 
   let req_msg = json!({
-    "type": msg::CompilerRequestType::RuntimeBundle,
+    "type": CompilerRequestType::RuntimeBundle,
     "target": "runtime",
     "rootNames": root_names,
     "sourceFileMap": module_graph_json,
@@ -1420,7 +1418,7 @@ pub async fn runtime_transpile(
   tsc_config::json_merge(&mut compiler_options, &user_options);
 
   let req_msg = json!({
-    "type": msg::CompilerRequestType::RuntimeTranspile,
+    "type": CompilerRequestType::RuntimeTranspile,
     "sources": sources,
     "compilerOptions": compiler_options,
   })
@@ -1561,6 +1559,34 @@ fn parse_deno_types(comment: &str) -> Option<String> {
   None
 }
 
+// Warning! The values in this enum are duplicated in js/compiler.ts
+// Update carefully!
+#[repr(i32)]
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub enum CompilerRequestType {
+  Compile = 0,
+  Bundle = 1,
+  RuntimeCompile = 2,
+  RuntimeBundle = 3,
+  RuntimeTranspile = 4,
+}
+
+impl Serialize for CompilerRequestType {
+  fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+  where
+    S: Serializer,
+  {
+    let value: i32 = match self {
+      CompilerRequestType::Compile => 0 as i32,
+      CompilerRequestType::Bundle => 1 as i32,
+      CompilerRequestType::RuntimeCompile => 2 as i32,
+      CompilerRequestType::RuntimeBundle => 3 as i32,
+      CompilerRequestType::RuntimeTranspile => 4 as i32,
+    };
+    Serialize::serialize(&value, serializer)
+  }
+}
+
 #[cfg(test)]
 mod tests {
   use super::*;
@@ -1640,7 +1666,7 @@ mod tests {
     let out = SourceFile {
       url: specifier.as_url().clone(),
       filename: PathBuf::from(p.to_str().unwrap().to_string()),
-      media_type: msg::MediaType::TypeScript,
+      media_type: MediaType::TypeScript,
       source_code: include_bytes!("./tests/002_hello.ts").to_vec().into(),
       types_header: None,
     };
@@ -1716,7 +1742,7 @@ mod tests {
     let out = SourceFile {
       url: specifier.as_url().clone(),
       filename: PathBuf::from(p.to_str().unwrap().to_string()),
-      media_type: msg::MediaType::TypeScript,
+      media_type: MediaType::TypeScript,
       source_code: include_bytes!("./tests/002_hello.ts").to_vec().into(),
       types_header: None,
     };