diff --git a/cli/lsp/README.md b/cli/lsp/README.md
index c43590f60f..a32deb5856 100644
--- a/cli/lsp/README.md
+++ b/cli/lsp/README.md
@@ -22,13 +22,38 @@ implement these in order to have a fully functioning client that integrates well
 with Deno:
 
 - `deno/cache` - This command will instruct Deno to attempt to cache a module
-  and all of its dependencies. It expects an argument of
-  `{ textDocument: TextDocumentIdentifier }` to be passed.
+  and all of its dependencies. If a `referrer` only is passed, then all
+  dependencies for the module specifier will be loaded. If there are values in
+  the `uris`, then only those `uris` will be cached.
+
+  It expects parameters of:
+
+  ```ts
+  interface CacheParams {
+    referrer: TextDocumentIdentifier;
+    uris: TextDocumentIdentifier[];
+  }
+  ```
 - `deno/performance` - Requests the return of the timing averages for the
   internal instrumentation of Deno.
+
+  It does not expect any parameters.
 - `deno/virtualTextDocument` - Requests a virtual text document from the LSP,
   which is a read only document that can be displayed in the client. This allows
   clients to access documents in the Deno cache, like remote modules and
-  TypeScript library files built into Deno. It also supports a special URL of
-  `deno:/status.md` which provides a markdown formatted text document that
-  contains details about the status of the LSP for display to a user.
+  TypeScript library files built into Deno. The Deno language server will encode
+  all internal files under the custom schema `deno:`, so clients should route
+  all requests for the `deno:` schema back to the `deno/virtualTextDocument`
+  API.
+
+  It also supports a special URL of `deno:/status.md` which provides a markdown
+  formatted text document that contains details about the status of the LSP for
+  display to a user.
+
+  It expects parameters of:
+
+  ```ts
+  interface VirtualTextDocumentParams {
+    textDocument: TextDocumentIdentifier;
+  }
+  ```
diff --git a/cli/lsp/analysis.rs b/cli/lsp/analysis.rs
index 8a1c565376..5e3ecab23d 100644
--- a/cli/lsp/analysis.rs
+++ b/cli/lsp/analysis.rs
@@ -456,11 +456,14 @@ impl CodeActionCollection {
   ) -> Result<(), AnyError> {
     if let Some(data) = diagnostic.data.clone() {
       let fix_data: DenoFixData = serde_json::from_value(data)?;
+      let title = if matches!(&diagnostic.code, Some(lsp::NumberOrString::String(code)) if code == "no-cache-data")
+      {
+        "Cache the data URL and its dependencies.".to_string()
+      } else {
+        format!("Cache \"{}\" and its dependencies.", fix_data.specifier)
+      };
       let code_action = lsp::CodeAction {
-        title: format!(
-          "Cache \"{}\" and its dependencies.",
-          fix_data.specifier
-        ),
+        title,
         kind: Some(lsp::CodeActionKind::QUICKFIX),
         diagnostics: Some(vec![diagnostic.clone()]),
         edit: None,
diff --git a/cli/lsp/diagnostics.rs b/cli/lsp/diagnostics.rs
index 8017d7e28c..705f0866de 100644
--- a/cli/lsp/diagnostics.rs
+++ b/cli/lsp/diagnostics.rs
@@ -295,9 +295,11 @@ pub async fn generate_dependency_diagnostics(
                 }
                 ResolvedDependency::Resolved(specifier) => {
                   if !(state_snapshot.documents.contains_key(&specifier) || sources.contains_key(&specifier)) {
-                    let is_local = specifier.scheme() == "file";
-                    let (code, message) = if is_local {
+                    let scheme = specifier.scheme();
+                    let (code, message) = if scheme == "file" {
                       (Some(lsp::NumberOrString::String("no-local".to_string())), format!("Unable to load a local module: \"{}\".\n  Please check the file path.", specifier))
+                    } else if scheme == "data" {
+                      (Some(lsp::NumberOrString::String("no-cache-data".to_string())), "Uncached data URL.".to_string())
                     } else {
                       (Some(lsp::NumberOrString::String("no-cache".to_string())), format!("Unable to load the remote module: \"{}\".", specifier))
                     };
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index 7c196d67eb..d167b53bb8 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -53,7 +53,7 @@ use super::tsc;
 use super::tsc::AssetDocument;
 use super::tsc::Assets;
 use super::tsc::TsServer;
-use super::utils;
+use super::urls;
 
 lazy_static! {
   static ref ABSTRACT_MODIFIER: Regex = Regex::new(r"\babstract\b").unwrap();
@@ -101,6 +101,8 @@ pub(crate) struct Inner {
   ts_fixable_diagnostics: Vec<String>,
   /// An abstraction that handles interactions with TypeScript.
   ts_server: TsServer,
+  /// A map of specifiers and URLs used to translate over the LSP.
+  pub url_map: urls::LspUrlMap,
 }
 
 impl LanguageServer {
@@ -131,6 +133,7 @@ impl Inner {
       sources,
       ts_fixable_diagnostics: Default::default(),
       ts_server: TsServer::new(),
+      url_map: Default::default(),
     }
   }
 
@@ -661,7 +664,7 @@ impl Inner {
       // already managed by the language service
       return;
     }
-    let specifier = utils::normalize_url(params.text_document.uri);
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
     self.documents.open(
       specifier.clone(),
       params.text_document.version,
@@ -678,7 +681,7 @@ impl Inner {
 
   async fn did_change(&mut self, params: DidChangeTextDocumentParams) {
     let mark = self.performance.mark("did_change");
-    let specifier = utils::normalize_url(params.text_document.uri);
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
     match self.documents.change(
       &specifier,
       params.text_document.version,
@@ -704,7 +707,7 @@ impl Inner {
       // already managed by the language service
       return;
     }
-    let specifier = utils::normalize_url(params.text_document.uri);
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
     self.documents.close(&specifier);
     self.navigation_trees.remove(&specifier);
 
@@ -802,7 +805,7 @@ impl Inner {
     params: DocumentFormattingParams,
   ) -> LspResult<Option<Vec<TextEdit>>> {
     let mark = self.performance.mark("formatting");
-    let specifier = utils::normalize_url(params.text_document.uri.clone());
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
     let file_text = self
       .documents
       .content(&specifier)
@@ -858,9 +861,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("hover");
-    let specifier = utils::normalize_url(
-      params.text_document_position_params.text_document.uri,
-    );
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position_params.text_document.uri);
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -898,7 +901,7 @@ impl Inner {
     }
 
     let mark = self.performance.mark("code_action");
-    let specifier = utils::normalize_url(params.text_document.uri);
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
     let fixable_diagnostics: Vec<&Diagnostic> = params
       .context
       .diagnostics
@@ -915,7 +918,9 @@ impl Inner {
             _ => false,
           },
           "deno" => match &d.code {
-            Some(NumberOrString::String(code)) => code == "no-cache",
+            Some(NumberOrString::String(code)) => {
+              code == "no-cache" || code == "no-cache-data"
+            }
             _ => false,
           },
           _ => false,
@@ -1053,7 +1058,7 @@ impl Inner {
     }
 
     let mark = self.performance.mark("code_lens");
-    let specifier = utils::normalize_url(params.text_document.uri);
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
     let line_index = self.get_line_index_sync(&specifier).unwrap();
     let navigation_tree =
       self.get_navigation_tree(&specifier).await.map_err(|err| {
@@ -1209,7 +1214,7 @@ impl Inner {
                 LspError::internal_error()
               })?;
               let implementation_location =
-                implementation.to_location(&line_index);
+                implementation.to_location(&line_index, self);
               if !(implementation_specifier == code_lens_data.specifier
                 && implementation_location.range.start == params.range.start)
               {
@@ -1222,11 +1227,13 @@ impl Inner {
               } else {
                 "1 implementation".to_string()
               };
-              let url = utils::normalize_specifier(&code_lens_data.specifier)
+              let url = self
+                .url_map
+                .normalize_specifier(&code_lens_data.specifier)
                 .map_err(|err| {
-                error!("{}", err);
-                LspError::internal_error()
-              })?;
+                  error!("{}", err);
+                  LspError::internal_error()
+                })?;
               Command {
                 title,
                 command: "deno.showReferences".to_string(),
@@ -1300,7 +1307,7 @@ impl Inner {
                 error!("Unable to get line index: {}", err);
                 LspError::internal_error()
               })?;
-              locations.push(reference.to_location(&line_index));
+              locations.push(reference.to_location(&line_index, self));
             }
             let command = if !locations.is_empty() {
               let title = if locations.len() > 1 {
@@ -1308,11 +1315,13 @@ impl Inner {
               } else {
                 "1 reference".to_string()
               };
-              let url = utils::normalize_specifier(&code_lens_data.specifier)
+              let url = self
+                .url_map
+                .normalize_specifier(&code_lens_data.specifier)
                 .map_err(|err| {
-                error!("{}", err);
-                LspError::internal_error()
-              })?;
+                  error!("{}", err);
+                  LspError::internal_error()
+                })?;
               Command {
                 title,
                 command: "deno.showReferences".to_string(),
@@ -1366,9 +1375,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("document_highlight");
-    let specifier = utils::normalize_url(
-      params.text_document_position_params.text_document.uri,
-    );
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position_params.text_document.uri);
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1412,8 +1421,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("references");
-    let specifier =
-      utils::normalize_url(params.text_document_position.text_document.uri);
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position.text_document.uri);
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1444,7 +1454,7 @@ impl Inner {
         // TODO(lucacasonato): handle error correctly
         let line_index =
           self.get_line_index(reference_specifier).await.unwrap();
-        results.push(reference.to_location(&line_index));
+        results.push(reference.to_location(&line_index, self));
       }
 
       self.performance.measure(mark);
@@ -1463,9 +1473,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("goto_definition");
-    let specifier = utils::normalize_url(
-      params.text_document_position_params.text_document.uri,
-    );
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position_params.text_document.uri);
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1503,8 +1513,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("completion");
-    let specifier =
-      utils::normalize_url(params.text_document_position.text_document.uri);
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position.text_document.uri);
     // TODO(lucacasonato): handle error correctly
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
@@ -1548,9 +1559,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("goto_implementation");
-    let specifier = utils::normalize_url(
-      params.text_document_position_params.text_document.uri,
-    );
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position_params.text_document.uri);
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1605,8 +1616,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("rename");
-    let specifier =
-      utils::normalize_url(params.text_document_position.text_document.uri);
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position.text_document.uri);
 
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
@@ -1710,9 +1722,9 @@ impl Inner {
       return Ok(None);
     }
     let mark = self.performance.mark("signature_help");
-    let specifier = utils::normalize_url(
-      params.text_document_position_params.text_document.uri,
-    );
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position_params.text_document.uri);
     let line_index =
       if let Some(line_index) = self.get_line_index_sync(&specifier) {
         line_index
@@ -1930,10 +1942,10 @@ impl Inner {
   /// in the Deno cache, including any of their dependencies.
   async fn cache(&mut self, params: CacheParams) -> LspResult<bool> {
     let mark = self.performance.mark("cache");
-    let referrer = utils::normalize_url(params.referrer.uri);
+    let referrer = self.url_map.normalize_url(&params.referrer.uri);
     if !params.uris.is_empty() {
       for identifier in &params.uris {
-        let specifier = utils::normalize_url(identifier.uri.clone());
+        let specifier = self.url_map.normalize_url(&identifier.uri);
         sources::cache(&specifier, &self.maybe_import_map)
           .await
           .map_err(|err| {
@@ -1976,7 +1988,7 @@ impl Inner {
     params: VirtualTextDocumentParams,
   ) -> LspResult<Option<String>> {
     let mark = self.performance.mark("virtual_text_document");
-    let specifier = utils::normalize_url(params.text_document.uri);
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
     let contents = if specifier.as_str() == "deno:/status.md" {
       let mut contents = String::new();
 
@@ -2170,15 +2182,15 @@ mod tests {
       ("initialize_request.json", LspResponse::RequestAny),
       ("initialized_notification.json", LspResponse::None),
       ("did_open_notification_asset.json", LspResponse::None),
-      ("hover_request_asset_01.json", LspResponse::RequestAny),
+      ("definition_request_asset.json", LspResponse::RequestAny),
       (
         "virtual_text_document_request.json",
         LspResponse::RequestAny,
       ),
       (
-        "hover_request_asset_02.json",
+        "hover_request_asset.json",
         LspResponse::Request(
-          4,
+          5,
           json!({
             "contents": [
               {
@@ -2807,6 +2819,7 @@ mod tests {
       ("initialize_request.json", LspResponse::RequestAny),
       ("initialized_notification.json", LspResponse::None),
       ("did_open_notification_asset.json", LspResponse::None),
+      ("references_request_asset.json", LspResponse::RequestAny),
       (
         "virtual_text_document_request.json",
         LspResponse::RequestAny,
diff --git a/cli/lsp/mod.rs b/cli/lsp/mod.rs
index 110bb4db2d..06f81646df 100644
--- a/cli/lsp/mod.rs
+++ b/cli/lsp/mod.rs
@@ -13,7 +13,7 @@ mod performance;
 mod sources;
 mod text;
 mod tsc;
-mod utils;
+mod urls;
 
 pub async fn start() -> Result<(), AnyError> {
   let stdin = tokio::io::stdin();
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index 8fc429d9d1..8adcb7f2b1 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -7,7 +7,6 @@ use super::language_server;
 use super::language_server::StateSnapshot;
 use super::text;
 use super::text::LineIndex;
-use super::utils;
 
 use crate::media_type::MediaType;
 use crate::tokio_util::create_basic_runtime;
@@ -480,40 +479,41 @@ impl DocumentSpan {
     language_server: &mut language_server::Inner,
   ) -> Option<lsp::LocationLink> {
     let target_specifier = resolve_url(&self.file_name).unwrap();
-    if let Ok(target_line_index) =
-      language_server.get_line_index(target_specifier).await
-    {
-      let target_uri = utils::normalize_file_name(&self.file_name).unwrap();
-      let (target_range, target_selection_range) =
-        if let Some(context_span) = &self.context_span {
-          (
-            context_span.to_range(&target_line_index),
-            self.text_span.to_range(&target_line_index),
-          )
-        } else {
-          (
-            self.text_span.to_range(&target_line_index),
-            self.text_span.to_range(&target_line_index),
-          )
-        };
-      let origin_selection_range =
-        if let Some(original_context_span) = &self.original_context_span {
-          Some(original_context_span.to_range(line_index))
-        } else if let Some(original_text_span) = &self.original_text_span {
-          Some(original_text_span.to_range(line_index))
-        } else {
-          None
-        };
-      let link = lsp::LocationLink {
-        origin_selection_range,
-        target_uri,
-        target_range,
-        target_selection_range,
+    let target_line_index = language_server
+      .get_line_index(target_specifier.clone())
+      .await
+      .ok()?;
+    let target_uri = language_server
+      .url_map
+      .normalize_specifier(&target_specifier)
+      .unwrap();
+    let (target_range, target_selection_range) =
+      if let Some(context_span) = &self.context_span {
+        (
+          context_span.to_range(&target_line_index),
+          self.text_span.to_range(&target_line_index),
+        )
+      } else {
+        (
+          self.text_span.to_range(&target_line_index),
+          self.text_span.to_range(&target_line_index),
+        )
       };
-      Some(link)
-    } else {
-      None
-    }
+    let origin_selection_range =
+      if let Some(original_context_span) = &self.original_context_span {
+        Some(original_context_span.to_range(line_index))
+      } else if let Some(original_text_span) = &self.original_text_span {
+        Some(original_text_span.to_range(line_index))
+      } else {
+        None
+      };
+    let link = lsp::LocationLink {
+      origin_selection_range,
+      target_uri,
+      target_range,
+      target_selection_range,
+    };
+    Some(link)
   }
 }
 
@@ -589,9 +589,16 @@ pub struct ImplementationLocation {
 }
 
 impl ImplementationLocation {
-  pub fn to_location(&self, line_index: &LineIndex) -> lsp::Location {
-    let uri =
-      utils::normalize_file_name(&self.document_span.file_name).unwrap();
+  pub(crate) fn to_location(
+    &self,
+    line_index: &LineIndex,
+    language_server: &mut language_server::Inner,
+  ) -> lsp::Location {
+    let specifier = resolve_url(&self.document_span.file_name).unwrap();
+    let uri = language_server
+      .url_map
+      .normalize_specifier(&specifier)
+      .unwrap();
     lsp::Location {
       uri,
       range: self.document_span.text_span.to_range(line_index),
@@ -633,8 +640,8 @@ impl RenameLocations {
     let mut text_document_edit_map: HashMap<Url, lsp::TextDocumentEdit> =
       HashMap::new();
     for location in self.locations.iter() {
-      let uri = utils::normalize_file_name(&location.document_span.file_name)?;
       let specifier = resolve_url(&location.document_span.file_name)?;
+      let uri = language_server.url_map.normalize_specifier(&specifier)?;
 
       // ensure TextDocumentEdit for `location.file_name`.
       if text_document_edit_map.get(&uri).is_none() {
@@ -852,9 +859,16 @@ pub struct ReferenceEntry {
 }
 
 impl ReferenceEntry {
-  pub fn to_location(&self, line_index: &LineIndex) -> lsp::Location {
-    let uri =
-      utils::normalize_file_name(&self.document_span.file_name).unwrap();
+  pub(crate) fn to_location(
+    &self,
+    line_index: &LineIndex,
+    language_server: &mut language_server::Inner,
+  ) -> lsp::Location {
+    let specifier = resolve_url(&self.document_span.file_name).unwrap();
+    let uri = language_server
+      .url_map
+      .normalize_specifier(&specifier)
+      .unwrap();
     lsp::Location {
       uri,
       range: self.document_span.text_span.to_range(line_index),
@@ -1237,7 +1251,7 @@ fn resolve(state: &mut State, args: Value) -> Result<Value, AnyError> {
         if specifier.starts_with("asset:///") {
           resolved.push(Some((
             specifier.clone(),
-            MediaType::from(specifier).as_ts_extension(),
+            MediaType::from(specifier).as_ts_extension().into(),
           )))
         } else if let Some(dependency) = dependencies.get(specifier) {
           let resolved_import =
@@ -1259,7 +1273,7 @@ fn resolve(state: &mut State, args: Value) -> Result<Value, AnyError> {
               let media_type = MediaType::from(&resolved_specifier);
               resolved.push(Some((
                 resolved_specifier.to_string(),
-                media_type.as_ts_extension(),
+                media_type.as_ts_extension().into(),
               )));
             } else if sources.contains_key(&resolved_specifier) {
               let media_type = if let Some(media_type) =
@@ -1271,7 +1285,7 @@ fn resolve(state: &mut State, args: Value) -> Result<Value, AnyError> {
               };
               resolved.push(Some((
                 resolved_specifier.to_string(),
-                media_type.as_ts_extension(),
+                media_type.as_ts_extension().into(),
               )));
             } else {
               resolved.push(None);
@@ -1289,7 +1303,7 @@ fn resolve(state: &mut State, args: Value) -> Result<Value, AnyError> {
       {
         resolved.push(Some((
           resolved_specifier.to_string(),
-          media_type.as_ts_extension(),
+          media_type.as_ts_extension().into(),
         )));
       } else {
         resolved.push(None);
diff --git a/cli/lsp/urls.rs b/cli/lsp/urls.rs
new file mode 100644
index 0000000000..a4af7d7b93
--- /dev/null
+++ b/cli/lsp/urls.rs
@@ -0,0 +1,174 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+use crate::file_fetcher::map_content_type;
+use crate::media_type::MediaType;
+
+use deno_core::error::AnyError;
+use deno_core::url::Url;
+use deno_core::ModuleSpecifier;
+use std::collections::HashMap;
+
+/// This is a partial guess as how URLs get encoded from the LSP.  We want to
+/// encode URLs sent to the LSP in the same way that they would be encoded back
+/// so that we have the same return encoding.
+const LSP_ENCODING: &percent_encoding::AsciiSet = &percent_encoding::CONTROLS
+  .add(b':')
+  .add(b';')
+  .add(b'=')
+  .add(b'@')
+  .add(b'[')
+  .add(b'\\')
+  .add(b']')
+  .add(b'^')
+  .add(b'|');
+
+fn hash_data_specifier(specifier: &ModuleSpecifier) -> String {
+  let mut file_name_str = specifier.path().to_string();
+  if let Some(query) = specifier.query() {
+    file_name_str.push('?');
+    file_name_str.push_str(query);
+  }
+  crate::checksum::gen(&[file_name_str.as_bytes()])
+}
+
+fn data_url_media_type(specifier: &ModuleSpecifier) -> MediaType {
+  let path = specifier.path();
+  let mut parts = path.splitn(2, ',');
+  let media_type_part =
+    percent_encoding::percent_decode_str(parts.next().unwrap())
+      .decode_utf8_lossy();
+  let (media_type, _) =
+    map_content_type(specifier, Some(media_type_part.into()));
+  media_type
+}
+
+/// A bi-directional map of URLs sent to the LSP client and internal module
+/// specifiers.  We need to map internal specifiers into `deno:` schema URLs
+/// to allow the Deno language server to manage these as virtual documents.
+#[derive(Debug, Default)]
+pub struct LspUrlMap {
+  specifier_to_url: HashMap<ModuleSpecifier, Url>,
+  url_to_specifier: HashMap<Url, ModuleSpecifier>,
+}
+
+impl LspUrlMap {
+  fn put(&mut self, specifier: ModuleSpecifier, url: Url) {
+    self.specifier_to_url.insert(specifier.clone(), url.clone());
+    self.url_to_specifier.insert(url, specifier);
+  }
+
+  fn get_url(&self, specifier: &ModuleSpecifier) -> Option<&Url> {
+    self.specifier_to_url.get(specifier)
+  }
+
+  fn get_specifier(&self, url: &Url) -> Option<&ModuleSpecifier> {
+    self.url_to_specifier.get(url)
+  }
+
+  /// Normalize a specifier that is used internally within Deno (or tsc) to a
+  /// URL that can be handled as a "virtual" document by an LSP client.
+  pub fn normalize_specifier(
+    &mut self,
+    specifier: &ModuleSpecifier,
+  ) -> Result<Url, AnyError> {
+    if let Some(url) = self.get_url(specifier) {
+      Ok(url.clone())
+    } else {
+      let url = if specifier.scheme() == "file" {
+        specifier.clone()
+      } else {
+        let specifier_str = if specifier.scheme() == "data" {
+          let media_type = data_url_media_type(specifier);
+          let extension = if media_type == MediaType::Unknown {
+            ""
+          } else {
+            media_type.as_ts_extension()
+          };
+          format!(
+            "deno:/{}/data_url{}",
+            hash_data_specifier(specifier),
+            extension
+          )
+        } else {
+          let path = specifier.as_str().replacen("://", "/", 1);
+          let path = percent_encoding::utf8_percent_encode(&path, LSP_ENCODING);
+          format!("deno:/{}", path)
+        };
+        let url = Url::parse(&specifier_str)?;
+        self.put(specifier.clone(), url.clone());
+        url
+      };
+      Ok(url)
+    }
+  }
+
+  /// Normalize URLs from the client, where "virtual" `deno:///` URLs are
+  /// converted into proper module specifiers.
+  pub fn normalize_url(&self, url: &Url) -> ModuleSpecifier {
+    if let Some(specifier) = self.get_specifier(url) {
+      specifier.clone()
+    } else {
+      url.clone()
+    }
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+  use deno_core::resolve_url;
+
+  #[test]
+  fn test_hash_data_specifier() {
+    let fixture = resolve_url("data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=").unwrap();
+    let actual = hash_data_specifier(&fixture);
+    assert_eq!(
+      actual,
+      "c21c7fc382b2b0553dc0864aa81a3acacfb7b3d1285ab5ae76da6abec213fb37"
+    );
+  }
+
+  #[test]
+  fn test_data_url_media_type() {
+    let fixture = resolve_url("data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=").unwrap();
+    let actual = data_url_media_type(&fixture);
+    assert_eq!(actual, MediaType::TypeScript);
+
+    let fixture = resolve_url("data:application/javascript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=").unwrap();
+    let actual = data_url_media_type(&fixture);
+    assert_eq!(actual, MediaType::JavaScript);
+
+    let fixture = resolve_url("data:text/plain;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=").unwrap();
+    let actual = data_url_media_type(&fixture);
+    assert_eq!(actual, MediaType::Unknown);
+  }
+
+  #[test]
+  fn test_lsp_url_map() {
+    let mut map = LspUrlMap::default();
+    let fixture = resolve_url("https://deno.land/x/pkg@1.0.0/mod.ts").unwrap();
+    let actual_url = map
+      .normalize_specifier(&fixture)
+      .expect("could not handle specifier");
+    let expected_url =
+      Url::parse("deno:/https/deno.land/x/pkg%401.0.0/mod.ts").unwrap();
+    assert_eq!(actual_url, expected_url);
+
+    let actual_specifier = map.normalize_url(&actual_url);
+    assert_eq!(actual_specifier, fixture);
+  }
+
+  #[test]
+  fn test_lsp_url_map_data() {
+    let mut map = LspUrlMap::default();
+    let fixture = resolve_url("data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=").unwrap();
+    let actual_url = map
+      .normalize_specifier(&fixture)
+      .expect("could not handle specifier");
+    let expected_url = Url::parse("deno:/c21c7fc382b2b0553dc0864aa81a3acacfb7b3d1285ab5ae76da6abec213fb37/data_url.ts").unwrap();
+    assert_eq!(actual_url, expected_url);
+
+    let actual_specifier = map.normalize_url(&actual_url);
+    assert_eq!(actual_specifier, fixture);
+  }
+}
diff --git a/cli/media_type.rs b/cli/media_type.rs
index db64b3922c..761de0ca03 100644
--- a/cli/media_type.rs
+++ b/cli/media_type.rs
@@ -121,8 +121,8 @@ impl MediaType {
   ///
   /// *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) -> String {
-    let ext = match self {
+  pub fn as_ts_extension(&self) -> &str {
+    match self {
       MediaType::JavaScript => ".js",
       MediaType::JSX => ".jsx",
       MediaType::TypeScript => ".ts",
@@ -138,13 +138,11 @@ impl MediaType {
       // JS for mapping purposes, though in reality, it is unlikely to ever be
       // passed to the compiler.
       MediaType::SourceMap => ".js",
-      // 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.
+      // TypeScript doesn't have an "unknown", so we will treat unknowns as JS
+      // for mapping purposes, though in reality, it is unlikely to ever be
+      // passed to the compiler.
       MediaType::Unknown => ".js",
-    };
-
-    ext.into()
+    }
   }
 
   /// Map the media type to a `ts.ScriptKind`
diff --git a/cli/tests/lsp/code_lens_request_asset.json b/cli/tests/lsp/code_lens_request_asset.json
index b9db86749e..6aa246ce5c 100644
--- a/cli/tests/lsp/code_lens_request_asset.json
+++ b/cli/tests/lsp/code_lens_request_asset.json
@@ -4,7 +4,7 @@
   "method": "textDocument/codeLens",
   "params": {
     "textDocument": {
-      "uri": "deno:/asset//lib.es2015.symbol.wellknown.d.ts"
+      "uri": "deno:/asset//lib.deno.shared_globals.d.ts"
     }
   }
 }
diff --git a/cli/tests/lsp/code_lens_resolve_request_asset.json b/cli/tests/lsp/code_lens_resolve_request_asset.json
index c225a62e2c..027af96b61 100644
--- a/cli/tests/lsp/code_lens_resolve_request_asset.json
+++ b/cli/tests/lsp/code_lens_resolve_request_asset.json
@@ -5,17 +5,17 @@
   "params": {
     "range": {
       "start": {
-        "line": 93,
-        "character": 10
+        "line": 416,
+        "character": 12
       },
       "end": {
-        "line": 93,
-        "character": 15
+        "line": 416,
+        "character": 19
       }
     },
     "data": {
-      "specifier": "asset:///lib.es2015.symbol.wellknown.d.ts",
-      "source": "implementations"
+      "specifier": "asset:///lib.deno.shared_globals.d.ts",
+      "source": "references"
     }
   }
 }
diff --git a/cli/tests/lsp/hover_request_asset_01.json b/cli/tests/lsp/definition_request_asset.json
similarity index 71%
rename from cli/tests/lsp/hover_request_asset_01.json
rename to cli/tests/lsp/definition_request_asset.json
index fb1c899a30..5e117cf147 100644
--- a/cli/tests/lsp/hover_request_asset_01.json
+++ b/cli/tests/lsp/definition_request_asset.json
@@ -1,14 +1,14 @@
 {
   "jsonrpc": "2.0",
   "id": 4,
-  "method": "textDocument/hover",
+  "method": "textDocument/definition",
   "params": {
     "textDocument": {
       "uri": "file:///a/file.ts"
     },
     "position": {
       "line": 0,
-      "character": 12
+      "character": 14
     }
   }
 }
diff --git a/cli/tests/lsp/did_open_notification_asset.json b/cli/tests/lsp/did_open_notification_asset.json
index 6288bbc534..413353f298 100644
--- a/cli/tests/lsp/did_open_notification_asset.json
+++ b/cli/tests/lsp/did_open_notification_asset.json
@@ -6,7 +6,7 @@
       "uri": "file:///a/file.ts",
       "languageId": "typescript",
       "version": 1,
-      "text": "console.log(\"hello deno!\");\n"
+      "text": "console.log(Date.now());\n"
     }
   }
 }
diff --git a/cli/tests/lsp/hover_request_asset_02.json b/cli/tests/lsp/hover_request_asset.json
similarity index 95%
rename from cli/tests/lsp/hover_request_asset_02.json
rename to cli/tests/lsp/hover_request_asset.json
index 30f4047096..2ae96acd5f 100644
--- a/cli/tests/lsp/hover_request_asset_02.json
+++ b/cli/tests/lsp/hover_request_asset.json
@@ -1,6 +1,6 @@
 {
   "jsonrpc": "2.0",
-  "id": 4,
+  "id": 5,
   "method": "textDocument/hover",
   "params": {
     "textDocument": {
diff --git a/cli/tests/lsp/references_request_asset.json b/cli/tests/lsp/references_request_asset.json
new file mode 100644
index 0000000000..6c2430e505
--- /dev/null
+++ b/cli/tests/lsp/references_request_asset.json
@@ -0,0 +1,17 @@
+{
+  "jsonrpc": "2.0",
+  "id": 2,
+  "method": "textDocument/references",
+  "params": {
+    "textDocument": {
+      "uri": "file:///a/file.ts"
+    },
+    "position": {
+      "line": 0,
+      "character": 3
+    },
+    "context": {
+      "includeDeclaration": true
+    }
+  }
+}
diff --git a/cli/tests/lsp/virtual_text_document_request.json b/cli/tests/lsp/virtual_text_document_request.json
index 08ad7a3ca4..6ffab4a356 100644
--- a/cli/tests/lsp/virtual_text_document_request.json
+++ b/cli/tests/lsp/virtual_text_document_request.json
@@ -1,10 +1,10 @@
 {
   "jsonrpc": "2.0",
-  "id": 2,
+  "id": 4,
   "method": "deno/virtualTextDocument",
   "params": {
     "textDocument": {
-      "uri": "deno:/asset//lib.es2015.symbol.wellknown.d.ts"
+      "uri": "deno:/asset//lib.deno.shared_globals.d.ts"
     }
   }
 }
diff --git a/cli/tsc.rs b/cli/tsc.rs
index 535447c543..5b6d00310a 100644
--- a/cli/tsc.rs
+++ b/cli/tsc.rs
@@ -383,7 +383,10 @@ fn resolve(state: &mut State, args: Value) -> Result<Value, AnyError> {
           } else {
             resolved_specifier.to_string()
           };
-          resolved.push((resolved_specifier_str, media_type.as_ts_extension()));
+          resolved.push((
+            resolved_specifier_str,
+            media_type.as_ts_extension().into(),
+          ));
         }
         // in certain situations, like certain dynamic imports, we won't have
         // the source file in the graph, so we will return a fake module to