1 files changed, 114 insertions, 11 deletions

diff --git a/cli/msg.rs b/cli/msg.rs
index 3e5000296..520d46fc2 100644
--- a/cli/msg.rs
+++ b/cli/msg.rs
@@ -1,10 +1,12 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-// Warning! The values in this enum are duplicated in js/compiler.ts
-// Update carefully!
 use serde::Serialize;
 use serde::Serializer;
+use std::path::Path;
+use std::path::PathBuf;
 
+// Warning! The values in this enum are duplicated in tsc/99_main_compiler.js
+// Update carefully!
 #[allow(non_camel_case_types)]
 #[repr(i32)]
 #[derive(Clone, Copy, PartialEq, Debug)]
@@ -12,10 +14,73 @@ pub enum MediaType {
   JavaScript = 0,
   JSX = 1,
   TypeScript = 2,
-  TSX = 3,
-  Json = 4,
-  Wasm = 5,
-  Unknown = 6,
+  Dts = 3,
+  TSX = 4,
+  Json = 5,
+  Wasm = 6,
+  BuildInfo = 7,
+  Unknown = 8,
+}
+
+impl<'a> From<&'a Path> for MediaType {
+  fn from(path: &'a Path) -> Self {
+    MediaType::from_path(path)
+  }
+}
+
+impl<'a> From<&'a PathBuf> for MediaType {
+  fn from(path: &'a PathBuf) -> Self {
+    MediaType::from_path(path)
+  }
+}
+
+impl<'a> From<&'a String> for MediaType {
+  fn from(specifier: &'a String) -> Self {
+    MediaType::from_path(&PathBuf::from(specifier))
+  }
+}
+
+impl MediaType {
+  fn from_path(path: &Path) -> Self {
+    match path.extension() {
+      None => MediaType::Unknown,
+      Some(os_str) => match os_str.to_str() {
+        Some("ts") => MediaType::TypeScript,
+        Some("tsx") => MediaType::TSX,
+        Some("js") => MediaType::JavaScript,
+        Some("jsx") => MediaType::JSX,
+        Some("mjs") => MediaType::JavaScript,
+        Some("cjs") => MediaType::JavaScript,
+        Some("json") => MediaType::Json,
+        Some("wasm") => MediaType::Wasm,
+        _ => MediaType::Unknown,
+      },
+    }
+  }
+
+  /// Convert a MediaType to a `ts.Extension`.
+  ///
+  /// *NOTE* This is defined in TypeScript as a string based enum.  Changes to
+  /// that enum in TypeScript should be reflected here.
+  pub fn as_ts_extension(&self) -> &str {
+    match self {
+      MediaType::JavaScript => ".js",
+      MediaType::JSX => ".jsx",
+      MediaType::TypeScript => ".ts",
+      MediaType::Dts => ".d.ts",
+      MediaType::TSX => ".tsx",
+      MediaType::Json => ".json",
+      // TypeScript doesn't have an "unknown", so we will treat WASM as JS for
+      // mapping purposes, though in reality, it is unlikely to ever be passed
+      // to the compiler.
+      MediaType::Wasm => ".js",
+      MediaType::BuildInfo => ".tsbuildinfo",
+      // TypeScript doesn't have an "unknown", so we will treat WASM as JS for
+      // mapping purposes, though in reality, it is unlikely to ever be passed
+      // to the compiler.
+      MediaType::Unknown => ".js",
+    }
+  }
 }
 
 impl Serialize for MediaType {
@@ -23,14 +88,16 @@ impl Serialize for MediaType {
   where
     S: Serializer,
   {
-    let value: i32 = match self {
+    let value = match self {
       MediaType::JavaScript => 0 as i32,
       MediaType::JSX => 1 as i32,
       MediaType::TypeScript => 2 as i32,
-      MediaType::TSX => 3 as i32,
-      MediaType::Json => 4 as i32,
-      MediaType::Wasm => 5 as i32,
-      MediaType::Unknown => 6 as i32,
+      MediaType::Dts => 3 as i32,
+      MediaType::TSX => 4 as i32,
+      MediaType::Json => 5 as i32,
+      MediaType::Wasm => 6 as i32,
+      MediaType::BuildInfo => 7 as i32,
+      MediaType::Unknown => 8 as i32,
     };
     Serialize::serialize(&value, serializer)
   }
@@ -41,9 +108,11 @@ pub fn enum_name_media_type(mt: MediaType) -> &'static str {
     MediaType::JavaScript => "JavaScript",
     MediaType::JSX => "JSX",
     MediaType::TypeScript => "TypeScript",
+    MediaType::Dts => "Dts",
     MediaType::TSX => "TSX",
     MediaType::Json => "Json",
     MediaType::Wasm => "Wasm",
+    MediaType::BuildInfo => "BuildInfo",
     MediaType::Unknown => "Unknown",
   }
 }
@@ -76,3 +145,37 @@ impl Serialize for CompilerRequestType {
     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);
+  }
+}