fix(#10815): lsp only responds to formatting for md, json, jsonc (#10816)

Fixes #10815

8 files changed, 529 insertions, 169 deletions

diff --git a/cli/file_fetcher.rs b/cli/file_fetcher.rs
index 7ab2f5cce..4d3048750 100644
--- a/cli/file_fetcher.rs
+++ b/cli/file_fetcher.rs
@@ -178,33 +178,7 @@ pub fn map_content_type(
   if let Some(content_type) = maybe_content_type {
     let mut content_types = content_type.split(';');
     let content_type = content_types.next().unwrap();
-    let media_type = match content_type.trim().to_lowercase().as_ref() {
-      "application/typescript"
-      | "text/typescript"
-      | "video/vnd.dlna.mpeg-tts"
-      | "video/mp2t"
-      | "application/x-typescript" => {
-        map_js_like_extension(specifier, MediaType::TypeScript)
-      }
-      "application/javascript"
-      | "text/javascript"
-      | "application/ecmascript"
-      | "text/ecmascript"
-      | "application/x-javascript"
-      | "application/node" => {
-        map_js_like_extension(specifier, MediaType::JavaScript)
-      }
-      "text/jsx" => MediaType::Jsx,
-      "text/tsx" => MediaType::Tsx,
-      "application/json" | "text/json" => MediaType::Json,
-      "application/wasm" => MediaType::Wasm,
-      // Handle plain and possibly webassembly
-      "text/plain" | "application/octet-stream" => MediaType::from(specifier),
-      _ => {
-        debug!("unknown content type: {}", content_type);
-        MediaType::Unknown
-      }
-    };
+    let media_type = MediaType::from_content_type(specifier, content_type);
     let charset = content_types
       .map(str::trim)
       .find_map(|s| s.strip_prefix("charset="))
@@ -216,55 +190,6 @@ pub fn map_content_type(
   }
 }
 
-/// Used to augment media types by using the path part of a module specifier to
-/// resolve to a more accurate media type.
-fn map_js_like_extension(
-  specifier: &ModuleSpecifier,
-  default: MediaType,
-) -> MediaType {
-  let path = if specifier.scheme() == "file" {
-    if let Ok(path) = specifier.to_file_path() {
-      path
-    } else {
-      PathBuf::from(specifier.path())
-    }
-  } else {
-    PathBuf::from(specifier.path())
-  };
-  match path.extension() {
-    None => default,
-    Some(os_str) => match os_str.to_str() {
-      None => default,
-      Some("jsx") => MediaType::Jsx,
-      Some("tsx") => MediaType::Tsx,
-      // Because DTS files do not have a separate media type, or a unique
-      // extension, we have to "guess" at those things that we consider that
-      // look like TypeScript, and end with `.d.ts` are DTS files.
-      Some("ts") => {
-        if default == MediaType::TypeScript {
-          match path.file_stem() {
-            None => default,
-            Some(os_str) => {
-              if let Some(file_stem) = os_str.to_str() {
-                if file_stem.ends_with(".d") {
-                  MediaType::Dts
-                } else {
-                  default
-                }
-              } else {
-                default
-              }
-            }
-          }
-        } else {
-          default
-        }
-      }
-      Some(_) => default,
-    },
-  }
-}
-
 /// Remove shebangs from the start of source code strings
 fn strip_shebang(mut value: String) -> String {
   if value.starts_with("#!") {
diff --git a/cli/lsp/completions.rs b/cli/lsp/completions.rs
index 95a13d59a..0e78b06e3 100644
--- a/cli/lsp/completions.rs
+++ b/cli/lsp/completions.rs
@@ -559,6 +559,7 @@ mod tests {
   use crate::http_cache::HttpCache;
   use crate::lsp::analysis;
   use crate::lsp::documents::DocumentCache;
+  use crate::lsp::documents::LanguageId;
   use crate::lsp::sources::Sources;
   use crate::media_type::MediaType;
   use deno_core::resolve_url;
@@ -567,15 +568,15 @@ mod tests {
   use tempfile::TempDir;
 
   fn mock_state_snapshot(
-    fixtures: &[(&str, &str, i32)],
+    fixtures: &[(&str, &str, i32, LanguageId)],
     source_fixtures: &[(&str, &str)],
     location: &Path,
   ) -> language_server::StateSnapshot {
     let mut documents = DocumentCache::default();
-    for (specifier, source, version) in fixtures {
+    for (specifier, source, version, language_id) in fixtures {
       let specifier =
         resolve_url(specifier).expect("failed to create specifier");
-      documents.open(specifier.clone(), *version, source);
+      documents.open(specifier.clone(), *version, language_id.clone(), source);
       let media_type = MediaType::from(&specifier);
       let parsed_module =
         analysis::parse_module(&specifier, source, &media_type).unwrap();
@@ -608,7 +609,7 @@ mod tests {
   }
 
   fn setup(
-    documents: &[(&str, &str, i32)],
+    documents: &[(&str, &str, i32, LanguageId)],
     sources: &[(&str, &str)],
   ) -> language_server::StateSnapshot {
     let temp_dir = TempDir::new().expect("could not create temp dir");
@@ -885,8 +886,13 @@ mod tests {
     };
     let state_snapshot = setup(
       &[
-        ("file:///a/b/c.ts", "import * as d from \"h\"", 1),
-        ("file:///a/c.ts", r#""#, 1),
+        (
+          "file:///a/b/c.ts",
+          "import * as d from \"h\"",
+          1,
+          LanguageId::TypeScript,
+        ),
+        ("file:///a/c.ts", r#""#, 1, LanguageId::TypeScript),
       ],
       &[("https://deno.land/x/a/b/c.ts", "console.log(1);\n")],
     );
diff --git a/cli/lsp/diagnostics.rs b/cli/lsp/diagnostics.rs
index 9b9035ac5..c069e4666 100644
--- a/cli/lsp/diagnostics.rs
+++ b/cli/lsp/diagnostics.rs
@@ -222,17 +222,6 @@ impl<'a> From<&'a diagnostics::Position> for lsp::Position {
   }
 }
 
-/// Check if diagnostics can be generated for the provided media type.
-pub fn is_diagnosable(media_type: MediaType) -> bool {
-  matches!(
-    media_type,
-    MediaType::TypeScript
-      | MediaType::JavaScript
-      | MediaType::Tsx
-      | MediaType::Jsx
-  )
-}
-
 fn get_diagnostic_message(diagnostic: &diagnostics::Diagnostic) -> String {
   if let Some(message) = diagnostic.message_text.clone() {
     message
@@ -322,13 +311,16 @@ async fn generate_lint_diagnostics(
     let mut diagnostics_vec = Vec::new();
     if workspace_settings.lint {
       for specifier in documents.open_specifiers() {
+        if !documents.is_diagnosable(specifier) {
+          continue;
+        }
         let version = documents.version(specifier);
         let current_version = collection
           .lock()
           .await
           .get_version(specifier, &DiagnosticSource::DenoLint);
         let media_type = MediaType::from(specifier);
-        if version != current_version && is_diagnosable(media_type) {
+        if version != current_version {
           if let Ok(Some(source_code)) = documents.content(specifier) {
             if let Ok(references) = analysis::get_lint_references(
               specifier,
@@ -366,12 +358,15 @@ async fn generate_ts_diagnostics(
       .open_specifiers()
       .iter()
       .filter_map(|&s| {
-        let version = snapshot.documents.version(s);
-        let current_version =
-          collection.get_version(s, &DiagnosticSource::TypeScript);
-        let media_type = MediaType::from(s);
-        if version != current_version && is_diagnosable(media_type) {
-          Some(s.clone())
+        if snapshot.documents.is_diagnosable(s) {
+          let version = snapshot.documents.version(s);
+          let current_version =
+            collection.get_version(s, &DiagnosticSource::TypeScript);
+          if version != current_version {
+            Some(s.clone())
+          } else {
+            None
+          }
         } else {
           None
         }
diff --git a/cli/lsp/documents.rs b/cli/lsp/documents.rs
index bdf80c5a8..048e4bedb 100644
--- a/cli/lsp/documents.rs
+++ b/cli/lsp/documents.rs
@@ -3,6 +3,9 @@
 use super::analysis;
 use super::text::LineIndex;
 
+use crate::media_type::MediaType;
+
+use deno_core::error::anyhow;
 use deno_core::error::custom_error;
 use deno_core::error::AnyError;
 use deno_core::error::Context;
@@ -10,6 +13,37 @@ use deno_core::ModuleSpecifier;
 use lspower::lsp::TextDocumentContentChangeEvent;
 use std::collections::HashMap;
 use std::ops::Range;
+use std::str::FromStr;
+
+/// A representation of the language id sent from the LSP client, which is used
+/// to determine how the document is handled within the language server.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum LanguageId {
+  JavaScript,
+  Jsx,
+  TypeScript,
+  Tsx,
+  Json,
+  JsonC,
+  Markdown,
+}
+
+impl FromStr for LanguageId {
+  type Err = AnyError;
+
+  fn from_str(s: &str) -> Result<Self, AnyError> {
+    match s {
+      "javascript" => Ok(Self::JavaScript),
+      "javascriptreact" => Ok(Self::Jsx),
+      "typescript" => Ok(Self::TypeScript),
+      "typescriptreact" => Ok(Self::Tsx),
+      "json" => Ok(Self::Json),
+      "jsonc" => Ok(Self::JsonC),
+      "markdown" => Ok(Self::Markdown),
+      _ => Err(anyhow!("Unsupported language id: {}", s)),
+    }
+  }
+}
 
 #[derive(Debug, PartialEq, Eq)]
 enum IndexValid {
@@ -29,6 +63,7 @@ impl IndexValid {
 #[derive(Debug, Clone)]
 pub struct DocumentData {
   bytes: Option<Vec<u8>>,
+  language_id: LanguageId,
   line_index: Option<LineIndex>,
   specifier: ModuleSpecifier,
   dependencies: Option<HashMap<String, analysis::Dependency>>,
@@ -36,9 +71,15 @@ pub struct DocumentData {
 }
 
 impl DocumentData {
-  pub fn new(specifier: ModuleSpecifier, version: i32, source: &str) -> Self {
+  pub fn new(
+    specifier: ModuleSpecifier,
+    version: i32,
+    language_id: LanguageId,
+    source: &str,
+  ) -> Self {
     Self {
       bytes: Some(source.as_bytes().to_owned()),
+      language_id,
       line_index: Some(LineIndex::new(source)),
       specifier,
       dependencies: None,
@@ -150,6 +191,39 @@ impl DocumentCache {
     doc.dependencies.clone()
   }
 
+  /// Determines if the specifier should be processed for diagnostics and other
+  /// related language server features.
+  pub fn is_diagnosable(&self, specifier: &ModuleSpecifier) -> bool {
+    if specifier.scheme() != "file" {
+      // otherwise we look at the media type for the specifier.
+      matches!(
+        MediaType::from(specifier),
+        MediaType::JavaScript
+          | MediaType::Jsx
+          | MediaType::TypeScript
+          | MediaType::Tsx
+          | MediaType::Dts
+      )
+    } else if let Some(doc_data) = self.docs.get(specifier) {
+      // if the document is in the document cache, then use the client provided
+      // language id to determine if the specifier is diagnosable.
+      matches!(
+        doc_data.language_id,
+        LanguageId::JavaScript
+          | LanguageId::Jsx
+          | LanguageId::TypeScript
+          | LanguageId::Tsx
+      )
+    } else {
+      false
+    }
+  }
+
+  /// Determines if the specifier can be processed for formatting.
+  pub fn is_formattable(&self, specifier: &ModuleSpecifier) -> bool {
+    self.docs.contains_key(specifier)
+  }
+
   pub fn len(&self) -> usize {
     self.docs.len()
   }
@@ -159,10 +233,16 @@ impl DocumentCache {
     doc.line_index.clone()
   }
 
-  pub fn open(&mut self, specifier: ModuleSpecifier, version: i32, text: &str) {
+  pub fn open(
+    &mut self,
+    specifier: ModuleSpecifier,
+    version: i32,
+    language_id: LanguageId,
+    source: &str,
+  ) {
     self.docs.insert(
       specifier.clone(),
-      DocumentData::new(specifier, version, text),
+      DocumentData::new(specifier, version, language_id, source),
     );
   }
 
@@ -219,7 +299,12 @@ mod tests {
     let mut document_cache = DocumentCache::default();
     let specifier = resolve_url("file:///a/b.ts").unwrap();
     let missing_specifier = resolve_url("file:///a/c.ts").unwrap();
-    document_cache.open(specifier.clone(), 1, "console.log(\"Hello Deno\");\n");
+    document_cache.open(
+      specifier.clone(),
+      1,
+      LanguageId::TypeScript,
+      "console.log(\"Hello Deno\");\n",
+    );
     assert!(document_cache.contains_key(&specifier));
     assert!(!document_cache.contains_key(&missing_specifier));
   }
@@ -228,7 +313,12 @@ mod tests {
   fn test_document_cache_change() {
     let mut document_cache = DocumentCache::default();
     let specifier = resolve_url("file:///a/b.ts").unwrap();
-    document_cache.open(specifier.clone(), 1, "console.log(\"Hello deno\");\n");
+    document_cache.open(
+      specifier.clone(),
+      1,
+      LanguageId::TypeScript,
+      "console.log(\"Hello deno\");\n",
+    );
     document_cache
       .change(
         &specifier,
@@ -259,7 +349,12 @@ mod tests {
   fn test_document_cache_change_utf16() {
     let mut document_cache = DocumentCache::default();
     let specifier = resolve_url("file:///a/b.ts").unwrap();
-    document_cache.open(specifier.clone(), 1, "console.log(\"Hello 🦕\");\n");
+    document_cache.open(
+      specifier.clone(),
+      1,
+      LanguageId::TypeScript,
+      "console.log(\"Hello 🦕\");\n",
+    );
     document_cache
       .change(
         &specifier,
@@ -285,4 +380,25 @@ mod tests {
       .expect("failed to get content");
     assert_eq!(actual, Some("console.log(\"Hello Deno\");\n".to_string()));
   }
+
+  #[test]
+  fn test_is_diagnosable() {
+    let mut document_cache = DocumentCache::default();
+    let specifier = resolve_url("file:///a/file.ts").unwrap();
+    assert!(!document_cache.is_diagnosable(&specifier));
+    document_cache.open(
+      specifier.clone(),
+      1,
+      LanguageId::TypeScript,
+      "console.log(\"hello world\");\n",
+    );
+    assert!(document_cache.is_diagnosable(&specifier));
+    let specifier =
+      resolve_url("asset:///lib.es2015.symbol.wellknown.d.ts").unwrap();
+    assert!(document_cache.is_diagnosable(&specifier));
+    let specifier = resolve_url("data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=").unwrap();
+    assert!(document_cache.is_diagnosable(&specifier));
+    let specifier = resolve_url("data:application/json;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=").unwrap();
+    assert!(!document_cache.is_diagnosable(&specifier));
+  }
 }
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index 3a751e319..20d5c1ee7 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -42,6 +42,7 @@ use super::config::SETTINGS_SECTION;
 use super::diagnostics;
 use super::diagnostics::DiagnosticSource;
 use super::documents::DocumentCache;
+use super::documents::LanguageId;
 use super::lsp_custom;
 use super::performance::Performance;
 use super::registries;
@@ -59,7 +60,6 @@ use crate::config_file::TsConfig;
 use crate::deno_dir;
 use crate::import_map::ImportMap;
 use crate::logger;
-use crate::lsp::diagnostics::is_diagnosable;
 use crate::media_type::MediaType;
 use crate::tools::fmt::format_file;
 use crate::tools::fmt::get_typescript_config;
@@ -611,17 +611,27 @@ impl Inner {
       // already managed by the language service
       return;
     }
+    let language_id = match params.text_document.language_id.parse() {
+      Ok(language_id) => language_id,
+      Err(err) => {
+        error!("{}", err);
+        LanguageId::TypeScript
+      }
+    };
     self.documents.open(
       specifier.clone(),
       params.text_document.version,
+      language_id,
       &params.text_document.text,
     );
-    self.analyze_dependencies(&specifier, &params.text_document.text);
-    self.performance.measure(mark);
 
-    if let Err(err) = self.diagnostics_server.update() {
-      error!("{}", err);
+    if self.documents.is_diagnosable(&specifier) {
+      self.analyze_dependencies(&specifier, &params.text_document.text);
+      if let Err(err) = self.diagnostics_server.update() {
+        error!("{}", err);
+      }
     }
+    self.performance.measure(mark);
   }
 
   async fn did_change(&mut self, params: DidChangeTextDocumentParams) {
@@ -632,15 +642,18 @@ impl Inner {
       params.text_document.version,
       params.content_changes,
     ) {
-      Ok(Some(source)) => self.analyze_dependencies(&specifier, &source),
+      Ok(Some(source)) => {
+        if self.documents.is_diagnosable(&specifier) {
+          self.analyze_dependencies(&specifier, &source);
+          if let Err(err) = self.diagnostics_server.update() {
+            error!("{}", err);
+          }
+        }
+      }
       Ok(_) => error!("No content returned from change."),
       Err(err) => error!("{}", err),
     }
     self.performance.measure(mark);
-
-    if let Err(err) = self.diagnostics_server.update() {
-      error!("{}", err);
-    }
   }
 
   async fn did_close(&mut self, params: DidCloseTextDocumentParams) {
@@ -655,10 +668,12 @@ impl Inner {
     self.documents.close(&specifier);
     self.navigation_trees.remove(&specifier);
 
-    self.performance.measure(mark);
-    if let Err(err) = self.diagnostics_server.update() {
-      error!("{}", err);
+    if self.documents.is_diagnosable(&specifier) {
+      if let Err(err) = self.diagnostics_server.update() {
+        error!("{}", err);
+      }
     }
+    self.performance.measure(mark);
   }
 
   async fn did_change_configuration(
@@ -751,11 +766,9 @@ impl Inner {
     params: DocumentSymbolParams,
   ) -> LspResult<Option<DocumentSymbolResponse>> {
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
-      return Ok(None);
-    }
-    let media_type = MediaType::from(&specifier);
-    if !is_diagnosable(media_type) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
 
@@ -798,8 +811,11 @@ impl Inner {
     &self,
     params: DocumentFormattingParams,
   ) -> LspResult<Option<Vec<TextEdit>>> {
-    let mark = self.performance.mark("formatting", Some(&params));
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
+    if !self.documents.is_formattable(&specifier) {
+      return Ok(None);
+    }
+    let mark = self.performance.mark("formatting", Some(&params));
     let file_text = self
       .documents
       .content(&specifier)
@@ -850,7 +866,9 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position_params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
     let mark = self.performance.mark("hover", Some(&params));
@@ -891,7 +909,9 @@ impl Inner {
     params: CodeActionParams,
   ) -> LspResult<Option<CodeActionResponse>> {
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
 
@@ -1054,7 +1074,8 @@ impl Inner {
     params: CodeLensParams,
   ) -> LspResult<Option<Vec<CodeLens>>> {
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier)
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
       || !self.config.get_workspace_settings().enabled_code_lens()
     {
       return Ok(None);
@@ -1366,7 +1387,9 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position_params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
 
@@ -1416,9 +1439,12 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
+
     let mark = self.performance.mark("references", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
@@ -1471,9 +1497,12 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position_params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
+
     let mark = self.performance.mark("goto_definition", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
@@ -1514,9 +1543,12 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
+
     let mark = self.performance.mark("completion", Some(&params));
     // Import specifiers are something wholly internal to Deno, so for
     // completions, we will use internal logic and if there are completions
@@ -1632,9 +1664,12 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position_params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
+
     let mark = self.performance.mark("goto_implementation", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
@@ -1680,11 +1715,13 @@ impl Inner {
     params: FoldingRangeParams,
   ) -> LspResult<Option<Vec<FoldingRange>>> {
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
-    let mark = self.performance.mark("folding_range", Some(&params));
 
+    let mark = self.performance.mark("folding_range", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1737,11 +1774,13 @@ impl Inner {
     params: CallHierarchyIncomingCallsParams,
   ) -> LspResult<Option<Vec<CallHierarchyIncomingCall>>> {
     let specifier = self.url_map.normalize_url(&params.item.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
-    let mark = self.performance.mark("incoming_calls", Some(&params));
 
+    let mark = self.performance.mark("incoming_calls", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1791,11 +1830,13 @@ impl Inner {
     params: CallHierarchyOutgoingCallsParams,
   ) -> LspResult<Option<Vec<CallHierarchyOutgoingCall>>> {
     let specifier = self.url_map.normalize_url(&params.item.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
-    let mark = self.performance.mark("outgoing_calls", Some(&params));
 
+    let mark = self.performance.mark("outgoing_calls", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1848,13 +1889,15 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position_params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
+
     let mark = self
       .performance
       .mark("prepare_call_hierarchy", Some(&params));
-
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1927,11 +1970,13 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
-    let mark = self.performance.mark("rename", Some(&params));
 
+    let mark = self.performance.mark("rename", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -2019,11 +2064,13 @@ impl Inner {
     params: SelectionRangeParams,
   ) -> LspResult<Option<Vec<SelectionRange>>> {
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
-    let mark = self.performance.mark("selection_range", Some(&params));
 
+    let mark = self.performance.mark("selection_range", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -2061,11 +2108,13 @@ impl Inner {
     params: SemanticTokensParams,
   ) -> LspResult<Option<SemanticTokensResult>> {
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
-    let mark = self.performance.mark("semantic_tokens_full", Some(&params));
 
+    let mark = self.performance.mark("semantic_tokens_full", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -2108,13 +2157,15 @@ impl Inner {
     params: SemanticTokensRangeParams,
   ) -> LspResult<Option<SemanticTokensRangeResult>> {
     let specifier = self.url_map.normalize_url(&params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
+
     let mark = self
       .performance
       .mark("semantic_tokens_range", Some(&params));
-
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -2158,9 +2209,12 @@ impl Inner {
     let specifier = self
       .url_map
       .normalize_url(&params.text_document_position_params.text_document.uri);
-    if !self.config.specifier_enabled(&specifier) {
+    if !self.documents.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
       return Ok(None);
     }
+
     let mark = self.performance.mark("signature_help", Some(&params));
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
@@ -2427,8 +2481,12 @@ impl Inner {
     &mut self,
     params: lsp_custom::CacheParams,
   ) -> LspResult<Option<Value>> {
-    let mark = self.performance.mark("cache", Some(&params));
     let referrer = self.url_map.normalize_url(&params.referrer.uri);
+    if !self.documents.is_diagnosable(&referrer) {
+      return Ok(None);
+    }
+
+    let mark = self.performance.mark("cache", Some(&params));
     if !params.uris.is_empty() {
       for identifier in &params.uris {
         let specifier = self.url_map.normalize_url(&identifier.uri);
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index 00be3e50b..6a476054f 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -2566,6 +2566,7 @@ mod tests {
   use crate::http_util::HeadersMap;
   use crate::lsp::analysis;
   use crate::lsp::documents::DocumentCache;
+  use crate::lsp::documents::LanguageId;
   use crate::lsp::sources::Sources;
   use crate::lsp::text::LineIndex;
   use std::path::Path;
@@ -2573,14 +2574,14 @@ mod tests {
   use tempfile::TempDir;
 
   fn mock_state_snapshot(
-    fixtures: &[(&str, &str, i32)],
+    fixtures: &[(&str, &str, i32, LanguageId)],
     location: &Path,
   ) -> StateSnapshot {
     let mut documents = DocumentCache::default();
-    for (specifier, source, version) in fixtures {
+    for (specifier, source, version, language_id) in fixtures {
       let specifier =
         resolve_url(specifier).expect("failed to create specifier");
-      documents.open(specifier.clone(), *version, source);
+      documents.open(specifier.clone(), *version, language_id.clone(), source);
       let media_type = MediaType::from(&specifier);
       if let Ok(parsed_module) =
         analysis::parse_module(&specifier, source, &media_type)
@@ -2605,7 +2606,7 @@ mod tests {
   fn setup(
     debug: bool,
     config: Value,
-    sources: &[(&str, &str, i32)],
+    sources: &[(&str, &str, i32, LanguageId)],
   ) -> (JsRuntime, StateSnapshot, PathBuf) {
     let temp_dir = TempDir::new().expect("could not create temp dir");
     let location = temp_dir.path().join("deps");
@@ -2688,7 +2689,12 @@ mod tests {
         "module": "esnext",
         "noEmit": true,
       }),
-      &[("file:///a.ts", r#"console.log("hello deno");"#, 1)],
+      &[(
+        "file:///a.ts",
+        r#"console.log("hello deno");"#,
+        1,
+        LanguageId::TypeScript,
+      )],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
     let result = request(
@@ -2733,7 +2739,12 @@ mod tests {
         "lib": ["esnext", "dom", "deno.ns"],
         "noEmit": true,
       }),
-      &[("file:///a.ts", r#"console.log(document.location);"#, 1)],
+      &[(
+        "file:///a.ts",
+        r#"console.log(document.location);"#,
+        1,
+        LanguageId::TypeScript,
+      )],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
     let result = request(
@@ -2766,6 +2777,7 @@ mod tests {
         console.log(b);
       "#,
         1,
+        LanguageId::TypeScript,
       )],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
@@ -2795,6 +2807,7 @@ mod tests {
         import { A } from ".";
         "#,
         1,
+        LanguageId::TypeScript,
       )],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
@@ -2848,6 +2861,7 @@ mod tests {
         console.log(b);
       "#,
         1,
+        LanguageId::TypeScript,
       )],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
@@ -2884,6 +2898,7 @@ mod tests {
         import * as test from
       "#,
         1,
+        LanguageId::TypeScript,
       )],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
@@ -2941,7 +2956,12 @@ mod tests {
         "lib": ["deno.ns", "deno.window"],
         "noEmit": true,
       }),
-      &[("file:///a.ts", r#"const url = new URL("b.js", import."#, 1)],
+      &[(
+        "file:///a.ts",
+        r#"const url = new URL("b.js", import."#,
+        1,
+        LanguageId::TypeScript,
+      )],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
     let result = request(
@@ -2998,6 +3018,7 @@ mod tests {
           }
         "#,
         1,
+        LanguageId::TypeScript,
       )],
     );
     let cache = HttpCache::new(&location);
@@ -3099,7 +3120,7 @@ mod tests {
         "lib": ["deno.ns", "deno.window"],
         "noEmit": true,
       }),
-      &[("file:///a.ts", fixture, 1)],
+      &[("file:///a.ts", fixture, 1, LanguageId::TypeScript)],
     );
     let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
     let result = request(
diff --git a/cli/media_type.rs b/cli/media_type.rs
index c83716f67..bfb869c13 100644
--- a/cli/media_type.rs
+++ b/cli/media_type.rs
@@ -1,5 +1,6 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
+use data_url::DataUrl;
 use deno_core::serde::Serialize;
 use deno_core::serde::Serializer;
 use deno_core::ModuleSpecifier;
@@ -45,34 +46,40 @@ impl fmt::Display for MediaType {
 
 impl<'a> From<&'a Path> for MediaType {
   fn from(path: &'a Path) -> Self {
-    MediaType::from_path(path)
+    Self::from_path(path)
   }
 }
 
 impl<'a> From<&'a PathBuf> for MediaType {
   fn from(path: &'a PathBuf) -> Self {
-    MediaType::from_path(path)
+    Self::from_path(path)
   }
 }
 
 impl<'a> From<&'a String> for MediaType {
   fn from(specifier: &'a String) -> Self {
-    MediaType::from_path(&PathBuf::from(specifier))
+    Self::from_path(&PathBuf::from(specifier))
   }
 }
 
 impl<'a> From<&'a ModuleSpecifier> for MediaType {
   fn from(specifier: &'a ModuleSpecifier) -> Self {
-    let path = if specifier.scheme() == "file" {
-      if let Ok(path) = specifier.to_file_path() {
-        path
+    if specifier.scheme() != "data" {
+      let path = if specifier.scheme() == "file" {
+        if let Ok(path) = specifier.to_file_path() {
+          path
+        } else {
+          PathBuf::from(specifier.path())
+        }
       } else {
         PathBuf::from(specifier.path())
-      }
+      };
+      Self::from_path(&path)
+    } else if let Ok(data_url) = DataUrl::process(specifier.as_str()) {
+      Self::from_content_type(specifier, data_url.mime_type().to_string())
     } else {
-      PathBuf::from(specifier.path())
-    };
-    MediaType::from_path(&path)
+      Self::Unknown
+    }
   }
 }
 
@@ -83,6 +90,40 @@ impl Default for MediaType {
 }
 
 impl MediaType {
+  pub fn from_content_type<S: AsRef<str>>(
+    specifier: &ModuleSpecifier,
+    content_type: S,
+  ) -> Self {
+    match content_type.as_ref().trim().to_lowercase().as_ref() {
+      "application/typescript"
+      | "text/typescript"
+      | "video/vnd.dlna.mpeg-tts"
+      | "video/mp2t"
+      | "application/x-typescript" => {
+        map_js_like_extension(specifier, Self::TypeScript)
+      }
+      "application/javascript"
+      | "text/javascript"
+      | "application/ecmascript"
+      | "text/ecmascript"
+      | "application/x-javascript"
+      | "application/node" => {
+        map_js_like_extension(specifier, Self::JavaScript)
+      }
+      "text/jsx" => Self::Jsx,
+      "text/tsx" => Self::Tsx,
+      "application/json" | "text/json" => Self::Json,
+      "application/wasm" => Self::Wasm,
+      // Handle plain and possibly webassembly
+      "text/plain" | "application/octet-stream"
+        if specifier.scheme() != "data" =>
+      {
+        Self::from(specifier)
+      }
+      _ => Self::Unknown,
+    }
+  }
+
   fn from_path(path: &Path) -> Self {
     match path.extension() {
       None => match path.file_name() {
@@ -197,6 +238,55 @@ where
   }
 }
 
+/// Used to augment media types by using the path part of a module specifier to
+/// resolve to a more accurate media type.
+fn map_js_like_extension(
+  specifier: &ModuleSpecifier,
+  default: MediaType,
+) -> MediaType {
+  let path = if specifier.scheme() == "file" {
+    if let Ok(path) = specifier.to_file_path() {
+      path
+    } else {
+      PathBuf::from(specifier.path())
+    }
+  } else {
+    PathBuf::from(specifier.path())
+  };
+  match path.extension() {
+    None => default,
+    Some(os_str) => match os_str.to_str() {
+      None => default,
+      Some("jsx") => MediaType::Jsx,
+      Some("tsx") => MediaType::Tsx,
+      // Because DTS files do not have a separate media type, or a unique
+      // extension, we have to "guess" at those things that we consider that
+      // look like TypeScript, and end with `.d.ts` are DTS files.
+      Some("ts") => {
+        if default == MediaType::TypeScript {
+          match path.file_stem() {
+            None => default,
+            Some(os_str) => {
+              if let Some(file_stem) = os_str.to_str() {
+                if file_stem.ends_with(".d") {
+                  MediaType::Dts
+                } else {
+                  default
+                }
+              } else {
+                default
+              }
+            }
+          }
+        } else {
+          default
+        }
+      }
+      Some(_) => default,
+    },
+  }
+}
+
 #[cfg(test)]
 mod tests {
   use super::*;
@@ -245,6 +335,9 @@ mod tests {
       ("https://deno.land/x/mod.ts", MediaType::TypeScript),
       ("https://deno.land/x/mod.js", MediaType::JavaScript),
       ("https://deno.land/x/mod.txt", MediaType::Unknown),
+      ("data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=", MediaType::TypeScript),
+      ("data:application/javascript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=", MediaType::JavaScript),
+      ("data:text/plain;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=", MediaType::Unknown),
     ];
 
     for (specifier, expected) in fixtures {
@@ -254,6 +347,52 @@ mod tests {
   }
 
   #[test]
+  fn test_from_content_type() {
+    let fixtures = vec![
+      (
+        "https://deno.land/x/mod.ts",
+        "application/typescript",
+        MediaType::TypeScript,
+      ),
+      (
+        "https://deno.land/x/mod.d.ts",
+        "application/typescript",
+        MediaType::Dts,
+      ),
+      ("https://deno.land/x/mod.tsx", "text/tsx", MediaType::Tsx),
+      (
+        "https://deno.land/x/mod.js",
+        "application/javascript",
+        MediaType::JavaScript,
+      ),
+      ("https://deno.land/x/mod.jsx", "text/jsx", MediaType::Jsx),
+      (
+        "https://deno.land/x/mod.ts",
+        "text/plain",
+        MediaType::TypeScript,
+      ),
+      (
+        "https://deno.land/x/mod.js",
+        "text/plain",
+        MediaType::JavaScript,
+      ),
+      (
+        "https://deno.land/x/mod.wasm",
+        "text/plain",
+        MediaType::Wasm,
+      ),
+    ];
+
+    for (specifier, content_type, expected) in fixtures {
+      let fixture = deno_core::resolve_url_or_path(specifier).unwrap();
+      assert_eq!(
+        MediaType::from_content_type(&fixture, content_type),
+        expected
+      );
+    }
+  }
+
+  #[test]
   fn test_serialization() {
     assert_eq!(json!(MediaType::JavaScript), json!(0));
     assert_eq!(json!(MediaType::Jsx), json!(1));
diff --git a/cli/tests/integration_tests_lsp.rs b/cli/tests/integration_tests_lsp.rs
index e4b963f2b..2fe984bca 100644
--- a/cli/tests/integration_tests_lsp.rs
+++ b/cli/tests/integration_tests_lsp.rs
@@ -2119,6 +2119,56 @@ fn lsp_format_json() {
 }
 
 #[test]
+fn lsp_json_no_diagnostics() {
+  let mut client = init("initialize_params.json");
+  client
+    .write_notification(
+      "textDocument/didOpen",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.json",
+          "languageId": "json",
+          "version": 1,
+          "text": "{\"key\":\"value\"}"
+        }
+      }),
+    )
+    .unwrap();
+
+  let (maybe_res, maybe_err) = client
+    .write_request(
+      "textDocument/semanticTokens/full",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.json"
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_err.is_none());
+  assert_eq!(maybe_res, Some(json!(null)));
+
+  let (maybe_res, maybe_err) = client
+    .write_request::<_, _, Value>(
+      "textDocument/hover",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.json"
+        },
+        "position": {
+          "line": 0,
+          "character": 3
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_err.is_none());
+  assert_eq!(maybe_res, Some(json!(null)));
+
+  shutdown(&mut client);
+}
+
+#[test]
 fn lsp_format_markdown() {
   let mut client = init("initialize_params.json");
   client
@@ -2174,6 +2224,56 @@ fn lsp_format_markdown() {
 }
 
 #[test]
+fn lsp_markdown_no_diagnostics() {
+  let mut client = init("initialize_params.json");
+  client
+    .write_notification(
+      "textDocument/didOpen",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.md",
+          "languageId": "markdown",
+          "version": 1,
+          "text": "# Hello World"
+        }
+      }),
+    )
+    .unwrap();
+
+  let (maybe_res, maybe_err) = client
+    .write_request(
+      "textDocument/semanticTokens/full",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.md"
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_err.is_none());
+  assert_eq!(maybe_res, Some(json!(null)));
+
+  let (maybe_res, maybe_err) = client
+    .write_request::<_, _, Value>(
+      "textDocument/hover",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.md"
+        },
+        "position": {
+          "line": 0,
+          "character": 3
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_err.is_none());
+  assert_eq!(maybe_res, Some(json!(null)));
+
+  shutdown(&mut client);
+}
+
+#[test]
 fn lsp_configuration_did_change() {
   let _g = http_server();
   let mut client = init("initialize_params_did_config_change.json");