refactor(lsp): refactor completions and add tests (#9789)

9 files changed, 787 insertions, 135 deletions

diff --git a/cli/lsp/capabilities.rs b/cli/lsp/capabilities.rs
index be318e7f3..82bb910bb 100644
--- a/cli/lsp/capabilities.rs
+++ b/cli/lsp/capabilities.rs
@@ -55,7 +55,12 @@ pub fn server_capabilities(
     )),
     hover_provider: Some(HoverProviderCapability::Simple(true)),
     completion_provider: Some(CompletionOptions {
-      all_commit_characters: None,
+      all_commit_characters: Some(vec![
+        ".".to_string(),
+        ",".to_string(),
+        ";".to_string(),
+        "(".to_string(),
+      ]),
       trigger_characters: Some(vec![
         ".".to_string(),
         "\"".to_string(),
@@ -66,7 +71,7 @@ pub fn server_capabilities(
         "<".to_string(),
         "#".to_string(),
       ]),
-      resolve_provider: None,
+      resolve_provider: Some(true),
       work_done_progress_options: WorkDoneProgressOptions {
         work_done_progress: None,
       },
@@ -77,7 +82,7 @@ pub fn server_capabilities(
         "(".to_string(),
         "<".to_string(),
       ]),
-      retrigger_characters: None,
+      retrigger_characters: Some(vec![")".to_string()]),
       work_done_progress_options: WorkDoneProgressOptions {
         work_done_progress: None,
       },
diff --git a/cli/lsp/config.rs b/cli/lsp/config.rs
index 8d31e3d54..201e5f23c 100644
--- a/cli/lsp/config.rs
+++ b/cli/lsp/config.rs
@@ -15,7 +15,7 @@ pub struct ClientCapabilities {
   pub workspace_did_change_watched_files: bool,
 }
 
-#[derive(Debug, Default, Clone, Deserialize)]
+#[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct CodeLensSettings {
   /// Flag for providing implementation code lenses.
@@ -30,13 +30,50 @@ pub struct CodeLensSettings {
   pub references_all_functions: bool,
 }
 
+impl Default for CodeLensSettings {
+  fn default() -> Self {
+    Self {
+      implementations: false,
+      references: false,
+      references_all_functions: false,
+    }
+  }
+}
+
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct CompletionSettings {
+  #[serde(default)]
+  pub complete_function_calls: bool,
+  #[serde(default)]
+  pub names: bool,
+  #[serde(default)]
+  pub paths: bool,
+  #[serde(default)]
+  pub auto_imports: bool,
+}
+
+impl Default for CompletionSettings {
+  fn default() -> Self {
+    Self {
+      complete_function_calls: false,
+      names: true,
+      paths: true,
+      auto_imports: true,
+    }
+  }
+}
+
 #[derive(Debug, Default, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct WorkspaceSettings {
   pub enable: bool,
   pub config: Option<String>,
   pub import_map: Option<String>,
-  pub code_lens: Option<CodeLensSettings>,
+  #[serde(default)]
+  pub code_lens: CodeLensSettings,
+  #[serde(default)]
+  pub suggest: CompletionSettings,
 
   #[serde(default)]
   pub lint: bool,
@@ -48,36 +85,7 @@ impl WorkspaceSettings {
   /// Determine if any code lenses are enabled at all.  This allows short
   /// circuiting when there are no code lenses enabled.
   pub fn enabled_code_lens(&self) -> bool {
-    if let Some(code_lens) = &self.code_lens {
-      // This should contain all the "top level" code lens references
-      code_lens.implementations || code_lens.references
-    } else {
-      false
-    }
-  }
-
-  pub fn enabled_code_lens_implementations(&self) -> bool {
-    if let Some(code_lens) = &self.code_lens {
-      code_lens.implementations
-    } else {
-      false
-    }
-  }
-
-  pub fn enabled_code_lens_references(&self) -> bool {
-    if let Some(code_lens) = &self.code_lens {
-      code_lens.references
-    } else {
-      false
-    }
-  }
-
-  pub fn enabled_code_lens_references_all_functions(&self) -> bool {
-    if let Some(code_lens) = &self.code_lens {
-      code_lens.references_all_functions
-    } else {
-      false
-    }
+    self.code_lens.implementations || self.code_lens.references
   }
 }
 
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index 96983dc52..3c3d82b3b 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -917,7 +917,7 @@ impl Inner {
       let mut code_lenses = cl.borrow_mut();
 
       // TSC Implementations Code Lens
-      if self.config.settings.enabled_code_lens_implementations() {
+      if self.config.settings.code_lens.implementations {
         let source = CodeLensSource::Implementations;
         match i.kind {
           tsc::ScriptElementKind::InterfaceElement => {
@@ -941,7 +941,7 @@ impl Inner {
       }
 
       // TSC References Code Lens
-      if self.config.settings.enabled_code_lens_references() {
+      if self.config.settings.code_lens.references {
         let source = CodeLensSource::References;
         if let Some(parent) = &mp {
           if parent.kind == tsc::ScriptElementKind::EnumElement {
@@ -950,11 +950,7 @@ impl Inner {
         }
         match i.kind {
           tsc::ScriptElementKind::FunctionElement => {
-            if self
-              .config
-              .settings
-              .enabled_code_lens_references_all_functions()
-            {
+            if self.config.settings.code_lens.references_all_functions {
               code_lenses.push(i.to_code_lens(
                 &line_index,
                 &specifier,
@@ -1358,7 +1354,6 @@ impl Inner {
     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) {
         line_index
@@ -1368,13 +1363,22 @@ impl Inner {
           specifier
         )));
       };
+    let trigger_character = if let Some(context) = &params.context {
+      context.trigger_character.clone()
+    } else {
+      None
+    };
+    let position =
+      line_index.offset_tsc(params.text_document_position.position)?;
     let req = tsc::RequestMethod::GetCompletions((
-      specifier,
-      line_index.offset_tsc(params.text_document_position.position)?,
-      tsc::UserPreferences {
-        // TODO(lucacasonato): enable this. see https://github.com/denoland/deno/pull/8651
-        include_completions_with_insert_text: Some(false),
-        ..Default::default()
+      specifier.clone(),
+      position,
+      tsc::GetCompletionsAtPositionOptions {
+        user_preferences: tsc::UserPreferences {
+          include_completions_with_insert_text: Some(true),
+          ..Default::default()
+        },
+        trigger_character,
       },
     ));
     let maybe_completion_info: Option<tsc::CompletionInfo> = self
@@ -1387,7 +1391,12 @@ impl Inner {
       })?;
 
     if let Some(completions) = maybe_completion_info {
-      let results = completions.into_completion_response(&line_index);
+      let results = completions.as_completion_response(
+        &line_index,
+        &self.config.settings.suggest,
+        &specifier,
+        position,
+      );
       self.performance.measure(mark);
       Ok(Some(results))
     } else {
@@ -1396,6 +1405,47 @@ impl Inner {
     }
   }
 
+  async fn completion_resolve(
+    &mut self,
+    params: CompletionItem,
+  ) -> LspResult<CompletionItem> {
+    let mark = self.performance.mark("completion_resolve");
+    if let Some(data) = &params.data {
+      let data: tsc::CompletionItemData = serde_json::from_value(data.clone())
+        .map_err(|err| {
+          error!("{}", err);
+          LspError::invalid_params(
+            "Could not decode data field of completion item.",
+          )
+        })?;
+      let req = tsc::RequestMethod::GetCompletionDetails(data.into());
+      let maybe_completion_info: Option<tsc::CompletionEntryDetails> = self
+        .ts_server
+        .request(self.snapshot(), req)
+        .await
+        .map_err(|err| {
+          error!("Unable to get completion info from TypeScript: {}", err);
+          LspError::internal_error()
+        })?;
+      if let Some(completion_info) = maybe_completion_info {
+        let completion_item = completion_info.as_completion_item(&params);
+        self.performance.measure(mark);
+        Ok(completion_item)
+      } else {
+        error!(
+          "Received an undefined response from tsc for completion details."
+        );
+        self.performance.measure(mark);
+        Ok(params)
+      }
+    } else {
+      self.performance.measure(mark);
+      Err(LspError::invalid_params(
+        "The completion item is missing the data field.",
+      ))
+    }
+  }
+
   async fn goto_implementation(
     &mut self,
     params: GotoImplementationParams,
@@ -1715,6 +1765,13 @@ impl lspower::LanguageServer for LanguageServer {
     self.0.lock().await.completion(params).await
   }
 
+  async fn completion_resolve(
+    &self,
+    params: CompletionItem,
+  ) -> LspResult<CompletionItem> {
+    self.0.lock().await.completion_resolve(params).await
+  }
+
   async fn goto_implementation(
     &self,
     params: GotoImplementationParams,
@@ -2741,6 +2798,58 @@ mod tests {
   }
 
   #[derive(Deserialize)]
+  struct CompletionResult {
+    pub result: Option<CompletionResponse>,
+  }
+
+  #[tokio::test]
+  async fn test_completions() {
+    let mut harness = LspTestHarness::new(vec![
+      ("initialize_request.json", LspResponse::RequestAny),
+      ("initialized_notification.json", LspResponse::None),
+      ("did_open_notification_completions.json", LspResponse::None),
+      (
+        "completion_request.json",
+        LspResponse::RequestAssert(|value| {
+          let response: CompletionResult =
+            serde_json::from_value(value).unwrap();
+          let result = response.result.unwrap();
+          match result {
+            CompletionResponse::List(list) => {
+              // there should be at least 90 completions for `Deno.`
+              assert!(list.items.len() > 90);
+            }
+            _ => panic!("unexpected result"),
+          }
+        }),
+      ),
+      (
+        "completion_resolve_request.json",
+        LspResponse::Request(
+          4,
+          json!({
+            "label": "build",
+            "kind": 6,
+            "detail": "const Deno.build: {\n    target: string;\n    arch: \"x86_64\";\n    os: \"darwin\" | \"linux\" | \"windows\";\n    vendor: string;\n    env?: string | undefined;\n}",
+            "documentation": {
+              "kind": "markdown",
+              "value": "Build related information."
+            },
+            "sortText": "1",
+            "insertTextFormat": 1,
+          }),
+        ),
+      ),
+      (
+        "shutdown_request.json",
+        LspResponse::Request(3, json!(null)),
+      ),
+      ("exit_notification.json", LspResponse::None),
+    ]);
+    harness.run().await;
+  }
+
+  #[derive(Deserialize)]
   struct PerformanceAverages {
     averages: Vec<PerformanceAverage>,
   }
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index 31434f529..a60f15eb8 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -3,6 +3,7 @@
 use super::analysis::CodeLensSource;
 use super::analysis::ResolvedDependency;
 use super::analysis::ResolvedDependencyErr;
+use super::config;
 use super::language_server;
 use super::language_server::StateSnapshot;
 use super::text;
@@ -35,11 +36,15 @@ use regex::Captures;
 use regex::Regex;
 use std::borrow::Cow;
 use std::collections::HashMap;
+use std::collections::HashSet;
 use std::thread;
 use text_size::TextSize;
 use tokio::sync::mpsc;
 use tokio::sync::oneshot;
 
+const FILE_EXTENSION_KIND_MODIFIERS: &[&str] =
+  &[".d.ts", ".ts", ".tsx", ".js", ".jsx", ".json"];
+
 type Request = (
   RequestMethod,
   StateSnapshot,
@@ -170,10 +175,10 @@ pub async fn get_asset(
   }
 }
 
-fn display_parts_to_string(parts: Vec<SymbolDisplayPart>) -> String {
+fn display_parts_to_string(parts: &[SymbolDisplayPart]) -> String {
   parts
-    .into_iter()
-    .map(|p| p.text)
+    .iter()
+    .map(|p| p.text.to_string())
     .collect::<Vec<String>>()
     .join("")
 }
@@ -276,7 +281,12 @@ fn replace_links(text: &str) -> String {
     .to_string()
 }
 
-#[derive(Debug, Clone, Deserialize, PartialEq, Eq)]
+fn parse_kind_modifier(kind_modifiers: &str) -> HashSet<&str> {
+  let re = Regex::new(r",|\s+").unwrap();
+  re.split(kind_modifiers).collect()
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
 pub enum ScriptElementKind {
   #[serde(rename = "")]
   Unknown,
@@ -348,42 +358,58 @@ pub enum ScriptElementKind {
   String,
 }
 
+impl Default for ScriptElementKind {
+  fn default() -> Self {
+    Self::Unknown
+  }
+}
+
 impl From<ScriptElementKind> for lsp::CompletionItemKind {
   fn from(kind: ScriptElementKind) -> Self {
-    use lspower::lsp::CompletionItemKind;
-
     match kind {
       ScriptElementKind::PrimitiveType | ScriptElementKind::Keyword => {
-        CompletionItemKind::Keyword
+        lsp::CompletionItemKind::Keyword
       }
-      ScriptElementKind::ConstElement => CompletionItemKind::Constant,
-      ScriptElementKind::LetElement
+      ScriptElementKind::ConstElement
+      | ScriptElementKind::LetElement
       | ScriptElementKind::VariableElement
       | ScriptElementKind::LocalVariableElement
-      | ScriptElementKind::Alias => CompletionItemKind::Variable,
+      | ScriptElementKind::Alias
+      | ScriptElementKind::ParameterElement => {
+        lsp::CompletionItemKind::Variable
+      }
       ScriptElementKind::MemberVariableElement
       | ScriptElementKind::MemberGetAccessorElement
       | ScriptElementKind::MemberSetAccessorElement => {
-        CompletionItemKind::Field
+        lsp::CompletionItemKind::Field
+      }
+      ScriptElementKind::FunctionElement
+      | ScriptElementKind::LocalFunctionElement => {
+        lsp::CompletionItemKind::Function
       }
-      ScriptElementKind::FunctionElement => CompletionItemKind::Function,
       ScriptElementKind::MemberFunctionElement
       | ScriptElementKind::ConstructSignatureElement
       | ScriptElementKind::CallSignatureElement
-      | ScriptElementKind::IndexSignatureElement => CompletionItemKind::Method,
-      ScriptElementKind::EnumElement => CompletionItemKind::Enum,
+      | ScriptElementKind::IndexSignatureElement => {
+        lsp::CompletionItemKind::Method
+      }
+      ScriptElementKind::EnumElement => lsp::CompletionItemKind::Enum,
+      ScriptElementKind::EnumMemberElement => {
+        lsp::CompletionItemKind::EnumMember
+      }
       ScriptElementKind::ModuleElement
-      | ScriptElementKind::ExternalModuleName => CompletionItemKind::Module,
-      ScriptElementKind::ClassElement | ScriptElementKind::TypeElement => {
-        CompletionItemKind::Class
+      | ScriptElementKind::ExternalModuleName => {
+        lsp::CompletionItemKind::Module
       }
-      ScriptElementKind::InterfaceElement => CompletionItemKind::Interface,
-      ScriptElementKind::Warning | ScriptElementKind::ScriptElement => {
-        CompletionItemKind::File
+      ScriptElementKind::ClassElement | ScriptElementKind::TypeElement => {
+        lsp::CompletionItemKind::Class
       }
-      ScriptElementKind::Directory => CompletionItemKind::Folder,
-      ScriptElementKind::String => CompletionItemKind::Constant,
-      _ => CompletionItemKind::Property,
+      ScriptElementKind::InterfaceElement => lsp::CompletionItemKind::Interface,
+      ScriptElementKind::Warning => lsp::CompletionItemKind::Text,
+      ScriptElementKind::ScriptElement => lsp::CompletionItemKind::File,
+      ScriptElementKind::Directory => lsp::CompletionItemKind::Folder,
+      ScriptElementKind::String => lsp::CompletionItemKind::Constant,
+      _ => lsp::CompletionItemKind::Property,
     }
   }
 }
@@ -432,16 +458,20 @@ pub struct QuickInfo {
 impl QuickInfo {
   pub fn to_hover(&self, line_index: &LineIndex) -> lsp::Hover {
     let mut contents = Vec::<lsp::MarkedString>::new();
-    if let Some(display_string) =
-      self.display_parts.clone().map(display_parts_to_string)
+    if let Some(display_string) = self
+      .display_parts
+      .clone()
+      .map(|p| display_parts_to_string(&p))
     {
       contents.push(lsp::MarkedString::from_language_code(
         "typescript".to_string(),
         display_string,
       ));
     }
-    if let Some(documentation) =
-      self.documentation.clone().map(display_parts_to_string)
+    if let Some(documentation) = self
+      .documentation
+      .clone()
+      .map(|p| display_parts_to_string(&p))
     {
       contents.push(lsp::MarkedString::from_markdown(documentation));
     }
@@ -824,6 +854,15 @@ impl FileTextChanges {
   }
 }
 
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct CodeAction {
+  description: String,
+  changes: Vec<FileTextChanges>,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  commands: Option<Vec<Value>>,
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
 #[serde(rename_all = "camelCase")]
 pub struct CodeFixAction {
@@ -882,99 +921,308 @@ impl ReferenceEntry {
 
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase")]
+pub struct CompletionEntryDetails {
+  name: String,
+  kind: ScriptElementKind,
+  kind_modifiers: String,
+  display_parts: Vec<SymbolDisplayPart>,
+  documentation: Option<Vec<SymbolDisplayPart>>,
+  tags: Option<Vec<JSDocTagInfo>>,
+  code_actions: Option<Vec<CodeAction>>,
+  source: Option<Vec<SymbolDisplayPart>>,
+}
+
+impl CompletionEntryDetails {
+  pub fn as_completion_item(
+    &self,
+    original_item: &lsp::CompletionItem,
+  ) -> lsp::CompletionItem {
+    let detail = if original_item.detail.is_some() {
+      original_item.detail.clone()
+    } else if !self.display_parts.is_empty() {
+      Some(replace_links(&display_parts_to_string(&self.display_parts)))
+    } else {
+      None
+    };
+    let documentation = if let Some(parts) = &self.documentation {
+      let mut value = display_parts_to_string(parts);
+      if let Some(tags) = &self.tags {
+        let tag_documentation = tags
+          .iter()
+          .map(get_tag_documentation)
+          .collect::<Vec<String>>()
+          .join("");
+        value = format!("{}\n\n{}", value, tag_documentation);
+      }
+      Some(lsp::Documentation::MarkupContent(lsp::MarkupContent {
+        kind: lsp::MarkupKind::Markdown,
+        value,
+      }))
+    } else {
+      None
+    };
+    // TODO(@kitsonk) add `self.code_actions`
+    // TODO(@kitsonk) add `use_code_snippet`
+
+    lsp::CompletionItem {
+      data: None,
+      detail,
+      documentation,
+      ..original_item.clone()
+    }
+  }
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
 pub struct CompletionInfo {
   entries: Vec<CompletionEntry>,
+  is_global_completion: bool,
   is_member_completion: bool,
+  is_new_identifier_location: bool,
+  metadata: Option<Value>,
+  optional_replacement_span: Option<TextSpan>,
 }
 
 impl CompletionInfo {
-  pub fn into_completion_response(
-    self,
+  pub fn as_completion_response(
+    &self,
     line_index: &LineIndex,
+    settings: &config::CompletionSettings,
+    specifier: &ModuleSpecifier,
+    position: u32,
   ) -> lsp::CompletionResponse {
     let items = self
       .entries
-      .into_iter()
-      .map(|entry| entry.into_completion_item(line_index))
+      .iter()
+      .map(|entry| {
+        entry
+          .as_completion_item(line_index, self, settings, specifier, position)
+      })
       .collect();
-    lsp::CompletionResponse::Array(items)
+    let is_incomplete = self
+      .metadata
+      .clone()
+      .map(|v| {
+        v.as_object()
+          .unwrap()
+          .get("isIncomplete")
+          .unwrap_or(&json!(false))
+          .as_bool()
+          .unwrap()
+      })
+      .unwrap_or(false);
+    lsp::CompletionResponse::List(lsp::CompletionList {
+      is_incomplete,
+      items,
+    })
   }
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct CompletionItemData {
+  pub specifier: ModuleSpecifier,
+  pub position: u32,
+  pub name: String,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  pub source: Option<String>,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  pub data: Option<Value>,
+  pub use_code_snippet: bool,
+}
+
+#[derive(Debug, Default, Deserialize, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct CompletionEntry {
+  name: String,
   kind: ScriptElementKind,
+  #[serde(skip_serializing_if = "Option::is_none")]
   kind_modifiers: Option<String>,
-  name: String,
   sort_text: String,
+  #[serde(skip_serializing_if = "Option::is_none")]
   insert_text: Option<String>,
+  #[serde(skip_serializing_if = "Option::is_none")]
   replacement_span: Option<TextSpan>,
+  #[serde(skip_serializing_if = "Option::is_none")]
   has_action: Option<bool>,
+  #[serde(skip_serializing_if = "Option::is_none")]
   source: Option<String>,
+  #[serde(skip_serializing_if = "Option::is_none")]
   is_recommended: Option<bool>,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  is_from_unchecked_file: Option<bool>,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  data: Option<Value>,
 }
 
 impl CompletionEntry {
-  pub fn into_completion_item(
-    self,
-    line_index: &LineIndex,
-  ) -> lsp::CompletionItem {
-    let mut item = lsp::CompletionItem {
-      label: self.name,
-      kind: Some(self.kind.into()),
-      sort_text: Some(self.sort_text.clone()),
-      // TODO(lucacasonato): missing commit_characters
-      ..Default::default()
-    };
+  fn get_commit_characters(
+    &self,
+    info: &CompletionInfo,
+    settings: &config::CompletionSettings,
+  ) -> Option<Vec<String>> {
+    if info.is_new_identifier_location {
+      return None;
+    }
 
-    if let Some(true) = self.is_recommended {
-      // Make sure isRecommended property always comes first
-      // https://github.com/Microsoft/vscode/issues/40325
-      item.preselect = Some(true);
-    } else if self.source.is_some() {
-      // De-prioritze auto-imports
-      // https://github.com/Microsoft/vscode/issues/40311
-      item.sort_text = Some("\u{ffff}".to_string() + &self.sort_text)
+    let mut commit_characters = vec![];
+    match self.kind {
+      ScriptElementKind::MemberGetAccessorElement
+      | ScriptElementKind::MemberSetAccessorElement
+      | ScriptElementKind::ConstructSignatureElement
+      | ScriptElementKind::CallSignatureElement
+      | ScriptElementKind::IndexSignatureElement
+      | ScriptElementKind::EnumElement
+      | ScriptElementKind::InterfaceElement => {
+        commit_characters.push(".");
+        commit_characters.push(";");
+      }
+      ScriptElementKind::ModuleElement
+      | ScriptElementKind::Alias
+      | ScriptElementKind::ConstElement
+      | ScriptElementKind::LetElement
+      | ScriptElementKind::VariableElement
+      | ScriptElementKind::LocalVariableElement
+      | ScriptElementKind::MemberVariableElement
+      | ScriptElementKind::ClassElement
+      | ScriptElementKind::FunctionElement
+      | ScriptElementKind::MemberFunctionElement
+      | ScriptElementKind::Keyword
+      | ScriptElementKind::ParameterElement => {
+        commit_characters.push(".");
+        commit_characters.push(",");
+        commit_characters.push(";");
+        if !settings.complete_function_calls {
+          commit_characters.push("(");
+        }
+      }
+      _ => (),
     }
 
-    match item.kind {
-      Some(lsp::CompletionItemKind::Function)
-      | Some(lsp::CompletionItemKind::Method) => {
-        item.insert_text_format = Some(lsp::InsertTextFormat::Snippet);
+    if commit_characters.is_empty() {
+      None
+    } else {
+      Some(commit_characters.into_iter().map(String::from).collect())
+    }
+  }
+
+  fn get_filter_text(&self) -> Option<String> {
+    // TODO(@kitsonk) this is actually quite a bit more complex.
+    // See `MyCompletionItem.getFilterText` in vscode completion.ts.
+    if self.name.starts_with('#') && self.insert_text.is_none() {
+      return Some(self.name.clone());
+    }
+
+    if let Some(insert_text) = &self.insert_text {
+      if insert_text.starts_with("this.") {
+        return None;
+      }
+      if insert_text.starts_with('[') {
+        let re = Regex::new(r#"^\[['"](.+)['"]\]$"#).unwrap();
+        let insert_text = re.replace(insert_text, ".$1").to_string();
+        return Some(insert_text);
       }
-      _ => {}
     }
 
-    let mut insert_text = self.insert_text;
-    let replacement_range: Option<lsp::Range> =
-      self.replacement_span.map(|span| span.to_range(line_index));
+    self.insert_text.clone()
+  }
 
-    // TODO(lucacasonato): port other special cases from https://github.com/theia-ide/typescript-language-server/blob/fdf28313833cd6216d00eb4e04dc7f00f4c04f09/server/src/completion.ts#L49-L55
+  pub fn as_completion_item(
+    &self,
+    line_index: &LineIndex,
+    info: &CompletionInfo,
+    settings: &config::CompletionSettings,
+    specifier: &ModuleSpecifier,
+    position: u32,
+  ) -> lsp::CompletionItem {
+    let mut label = self.name.clone();
+    let mut kind: Option<lsp::CompletionItemKind> =
+      Some(self.kind.clone().into());
 
-    if let Some(kind_modifiers) = self.kind_modifiers {
-      if kind_modifiers.contains("\\optional\\") {
+    let sort_text = if self.source.is_some() {
+      Some(format!("\u{ffff}{}", self.sort_text))
+    } else {
+      Some(self.sort_text.clone())
+    };
+
+    let preselect = self.is_recommended;
+    let use_code_snippet = settings.complete_function_calls
+      && (kind == Some(lsp::CompletionItemKind::Function)
+        || kind == Some(lsp::CompletionItemKind::Method));
+    // TODO(@kitsonk) missing from types: https://github.com/gluon-lang/lsp-types/issues/204
+    let _commit_characters = self.get_commit_characters(info, settings);
+    let mut insert_text = self.insert_text.clone();
+    let range = self.replacement_span.clone();
+    let mut filter_text = self.get_filter_text();
+    let mut tags = None;
+    let mut detail = None;
+
+    if let Some(kind_modifiers) = &self.kind_modifiers {
+      let kind_modifiers = parse_kind_modifier(kind_modifiers);
+      if kind_modifiers.contains("optional") {
         if insert_text.is_none() {
-          insert_text = Some(item.label.clone());
+          insert_text = Some(label.clone());
         }
-        if item.filter_text.is_none() {
-          item.filter_text = Some(item.label.clone());
+        if filter_text.is_none() {
+          filter_text = Some(label.clone());
+        }
+        label += "?";
+      }
+      if kind_modifiers.contains("deprecated") {
+        tags = Some(vec![lsp::CompletionItemTag::Deprecated]);
+      }
+      if kind_modifiers.contains("color") {
+        kind = Some(lsp::CompletionItemKind::Color);
+      }
+      if self.kind == ScriptElementKind::ScriptElement {
+        for ext_modifier in FILE_EXTENSION_KIND_MODIFIERS {
+          if kind_modifiers.contains(ext_modifier) {
+            detail = if self.name.to_lowercase().ends_with(ext_modifier) {
+              Some(self.name.clone())
+            } else {
+              Some(format!("{}{}", self.name, ext_modifier))
+            };
+            break;
+          }
         }
-        item.label += "?";
       }
     }
 
-    if let Some(insert_text) = insert_text {
-      if let Some(replacement_range) = replacement_range {
-        item.text_edit = Some(lsp::CompletionTextEdit::Edit(
-          lsp::TextEdit::new(replacement_range, insert_text),
-        ));
+    let text_edit =
+      if let (Some(text_span), Some(new_text)) = (range, insert_text) {
+        let range = text_span.to_range(line_index);
+        let insert_replace_edit = lsp::InsertReplaceEdit {
+          new_text,
+          insert: range,
+          replace: range,
+        };
+        Some(insert_replace_edit.into())
       } else {
-        item.insert_text = Some(insert_text);
-      }
-    }
+        None
+      };
+
+    let data = CompletionItemData {
+      specifier: specifier.clone(),
+      position,
+      name: self.name.clone(),
+      source: self.source.clone(),
+      data: self.data.clone(),
+      use_code_snippet,
+    };
 
-    item
+    lsp::CompletionItem {
+      label,
+      kind,
+      sort_text,
+      preselect,
+      text_edit,
+      filter_text,
+      detail,
+      tags,
+      data: Some(serde_json::to_value(data).unwrap()),
+      ..Default::default()
+    }
   }
 }
 
@@ -1016,18 +1264,18 @@ pub struct SignatureHelpItem {
 
 impl SignatureHelpItem {
   pub fn into_signature_information(self) -> lsp::SignatureInformation {
-    let prefix_text = display_parts_to_string(self.prefix_display_parts);
+    let prefix_text = display_parts_to_string(&self.prefix_display_parts);
     let params_text = self
       .parameters
       .iter()
-      .map(|param| display_parts_to_string(param.display_parts.clone()))
+      .map(|param| display_parts_to_string(&param.display_parts))
       .collect::<Vec<String>>()
       .join(", ");
-    let suffix_text = display_parts_to_string(self.suffix_display_parts);
+    let suffix_text = display_parts_to_string(&self.suffix_display_parts);
     lsp::SignatureInformation {
       label: format!("{}{}{}", prefix_text, params_text, suffix_text),
       documentation: Some(lsp::Documentation::String(display_parts_to_string(
-        self.documentation,
+        &self.documentation,
       ))),
       parameters: Some(
         self
@@ -1054,10 +1302,10 @@ impl SignatureHelpParameter {
   pub fn into_parameter_information(self) -> lsp::ParameterInformation {
     lsp::ParameterInformation {
       label: lsp::ParameterLabel::Simple(display_parts_to_string(
-        self.display_parts,
+        &self.display_parts,
       )),
       documentation: Some(lsp::Documentation::String(display_parts_to_string(
-        self.documentation,
+        &self.documentation,
       ))),
     }
   }
@@ -1481,6 +1729,15 @@ pub enum IncludePackageJsonAutoImports {
 
 #[derive(Debug, Default, Serialize)]
 #[serde(rename_all = "camelCase")]
+pub struct GetCompletionsAtPositionOptions {
+  #[serde(flatten)]
+  pub user_preferences: UserPreferences,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  pub trigger_character: Option<String>,
+}
+
+#[derive(Debug, Default, Serialize)]
+#[serde(rename_all = "camelCase")]
 pub struct UserPreferences {
   #[serde(skip_serializing_if = "Option::is_none")]
   pub disable_suggestions: Option<bool>,
@@ -1542,6 +1799,30 @@ pub struct SignatureHelpTriggerReason {
   pub trigger_character: Option<String>,
 }
 
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct GetCompletionDetailsArgs {
+  pub specifier: ModuleSpecifier,
+  pub position: u32,
+  pub name: String,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  pub source: Option<String>,
+  #[serde(skip_serializing_if = "Option::is_none")]
+  pub data: Option<Value>,
+}
+
+impl From<CompletionItemData> for GetCompletionDetailsArgs {
+  fn from(item_data: CompletionItemData) -> Self {
+    Self {
+      specifier: item_data.specifier,
+      position: item_data.position,
+      name: item_data.name,
+      source: item_data.source,
+      data: item_data.data,
+    }
+  }
+}
+
 /// Methods that are supported by the Language Service in the compiler isolate.
 #[derive(Debug)]
 pub enum RequestMethod {
@@ -1554,7 +1835,9 @@ pub enum RequestMethod {
   /// Retrieve code fixes for a range of a file with the provided error codes.
   GetCodeFixes((ModuleSpecifier, u32, u32, Vec<String>)),
   /// Get completion information at a given position (IntelliSense).
-  GetCompletions((ModuleSpecifier, u32, UserPreferences)),
+  GetCompletions((ModuleSpecifier, u32, GetCompletionsAtPositionOptions)),
+  /// Get details about a specific completion entry.
+  GetCompletionDetails(GetCompletionDetailsArgs),
   /// Retrieve the combined code fixes for a fix id for a module.
   GetCombinedCodeFix((ModuleSpecifier, Value)),
   /// Get declaration information for a specific position.
@@ -1626,6 +1909,11 @@ impl RequestMethod {
         "specifier": specifier,
         "fixId": fix_id,
       }),
+      RequestMethod::GetCompletionDetails(args) => json!({
+        "id": id,
+        "method": "getCompletionDetails",
+        "args": args
+      }),
       RequestMethod::GetCompletions((specifier, position, preferences)) => {
         json!({
           "id": id,
@@ -1738,6 +2026,7 @@ mod tests {
   use crate::lsp::analysis;
   use crate::lsp::documents::DocumentCache;
   use crate::lsp::sources::Sources;
+  use crate::lsp::text::LineIndex;
   use std::path::Path;
   use std::path::PathBuf;
   use tempfile::TempDir;
@@ -2228,4 +2517,170 @@ mod tests {
       })
     );
   }
+
+  #[test]
+  fn test_completion_entry_filter_text() {
+    let fixture = CompletionEntry {
+      kind: ScriptElementKind::MemberVariableElement,
+      name: "['foo']".to_string(),
+      insert_text: Some("['foo']".to_string()),
+      ..Default::default()
+    };
+    let actual = fixture.get_filter_text();
+    assert_eq!(actual, Some(".foo".to_string()));
+  }
+
+  #[test]
+  fn test_completions() {
+    let fixture = r#"
+      import { B } from "https://deno.land/x/b/mod.ts";
+
+      const b = new B();
+
+      console.
+    "#;
+    let line_index = LineIndex::new(fixture);
+    let position = line_index
+      .offset_tsc(lsp::Position {
+        line: 5,
+        character: 16,
+      })
+      .unwrap();
+    let (mut runtime, state_snapshot, _) = setup(
+      false,
+      json!({
+        "target": "esnext",
+        "module": "esnext",
+        "lib": ["deno.ns", "deno.window"],
+        "noEmit": true,
+      }),
+      &[("file:///a.ts", fixture, 1)],
+    );
+    let specifier = resolve_url("file:///a.ts").expect("could not resolve url");
+    let result = request(
+      &mut runtime,
+      state_snapshot.clone(),
+      RequestMethod::GetDiagnostics(vec![specifier.clone()]),
+    );
+    assert!(result.is_ok());
+    let result = request(
+      &mut runtime,
+      state_snapshot.clone(),
+      RequestMethod::GetCompletions((
+        specifier.clone(),
+        position,
+        GetCompletionsAtPositionOptions {
+          user_preferences: UserPreferences {
+            include_completions_with_insert_text: Some(true),
+            ..Default::default()
+          },
+          trigger_character: Some(".".to_string()),
+        },
+      )),
+    );
+    assert!(result.is_ok());
+    let response: CompletionInfo =
+      serde_json::from_value(result.unwrap()).unwrap();
+    assert_eq!(response.entries.len(), 20);
+    let result = request(
+      &mut runtime,
+      state_snapshot,
+      RequestMethod::GetCompletionDetails(GetCompletionDetailsArgs {
+        specifier,
+        position,
+        name: "log".to_string(),
+        source: None,
+        data: None,
+      }),
+    );
+    assert!(result.is_ok());
+    let response = result.unwrap();
+    assert_eq!(
+      response,
+      json!({
+        "name": "log",
+        "kindModifiers": "declare",
+        "kind": "method",
+        "displayParts": [
+          {
+            "text": "(",
+            "kind": "punctuation"
+          },
+          {
+            "text": "method",
+            "kind": "text"
+          },
+          {
+            "text": ")",
+            "kind": "punctuation"
+          },
+          {
+            "text": " ",
+            "kind": "space"
+          },
+          {
+            "text": "Console",
+            "kind": "interfaceName"
+          },
+          {
+            "text": ".",
+            "kind": "punctuation"
+          },
+          {
+            "text": "log",
+            "kind": "methodName"
+          },
+          {
+            "text": "(",
+            "kind": "punctuation"
+          },
+          {
+            "text": "...",
+            "kind": "punctuation"
+          },
+          {
+            "text": "data",
+            "kind": "parameterName"
+          },
+          {
+            "text": ":",
+            "kind": "punctuation"
+          },
+          {
+            "text": " ",
+            "kind": "space"
+          },
+          {
+            "text": "any",
+            "kind": "keyword"
+          },
+          {
+            "text": "[",
+            "kind": "punctuation"
+          },
+          {
+            "text": "]",
+            "kind": "punctuation"
+          },
+          {
+            "text": ")",
+            "kind": "punctuation"
+          },
+          {
+            "text": ":",
+            "kind": "punctuation"
+          },
+          {
+            "text": " ",
+            "kind": "space"
+          },
+          {
+            "text": "void",
+            "kind": "keyword"
+          }
+        ],
+        "documentation": []
+      })
+    );
+  }
 }
diff --git a/cli/tests/lsp/completion_request.json b/cli/tests/lsp/completion_request.json
new file mode 100644
index 000000000..81bf719a9
--- /dev/null
+++ b/cli/tests/lsp/completion_request.json
@@ -0,0 +1,18 @@
+{
+  "jsonrpc": "2.0",
+  "id": 2,
+  "method": "textDocument/completion",
+  "params": {
+    "textDocument": {
+      "uri": "file:///a/file.ts"
+    },
+    "position": {
+      "line": 0,
+      "character": 5
+    },
+    "context": {
+      "triggerKind": 2,
+      "triggerCharacter": "."
+    }
+  }
+}
diff --git a/cli/tests/lsp/completion_resolve_request.json b/cli/tests/lsp/completion_resolve_request.json
new file mode 100644
index 000000000..c176a431e
--- /dev/null
+++ b/cli/tests/lsp/completion_resolve_request.json
@@ -0,0 +1,17 @@
+{
+  "jsonrpc": "2.0",
+  "id": 4,
+  "method": "completionItem/resolve",
+  "params": {
+    "label": "build",
+    "kind": 6,
+    "sortText": "1",
+    "insertTextFormat": 1,
+    "data": {
+      "specifier": "file:///a/file.ts",
+      "position": 5,
+      "name": "build",
+      "useCodeSnippet": false
+    }
+  }
+}
diff --git a/cli/tests/lsp/did_open_notification_completions.json b/cli/tests/lsp/did_open_notification_completions.json
new file mode 100644
index 000000000..edcdc9373
--- /dev/null
+++ b/cli/tests/lsp/did_open_notification_completions.json
@@ -0,0 +1,12 @@
+{
+  "jsonrpc": "2.0",
+  "method": "textDocument/didOpen",
+  "params": {
+    "textDocument": {
+      "uri": "file:///a/file.ts",
+      "languageId": "typescript",
+      "version": 1,
+      "text": "Deno."
+    }
+  }
+}
diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index f8eabc890..c84c2365c 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -594,6 +594,22 @@ delete Object.prototype.__proto__;
           ),
         );
       }
+      case "getCompletionDetails": {
+        debug("request", request);
+        return respond(
+          id,
+          languageService.getCompletionEntryDetails(
+            request.args.specifier,
+            request.args.position,
+            request.args.name,
+            undefined,
+            request.args.source,
+            undefined,
+            // @ts-expect-error this exists in 4.3 but not part of the d.ts
+            request.args.data,
+          ),
+        );
+      }
       case "getCompletions": {
         return respond(
           id,
diff --git a/cli/tsc/compiler.d.ts b/cli/tsc/compiler.d.ts
index d37b56c06..a3200469c 100644
--- a/cli/tsc/compiler.d.ts
+++ b/cli/tsc/compiler.d.ts
@@ -51,6 +51,7 @@ declare global {
     | GetAsset
     | GetCodeFixes
     | GetCombinedCodeFix
+    | GetCompletionDetails
     | GetCompletionsRequest
     | GetDefinitionRequest
     | GetDiagnosticsRequest
@@ -102,11 +103,22 @@ declare global {
     fixId: {};
   }
 
+  interface GetCompletionDetails extends BaseLanguageServerRequest {
+    method: "getCompletionDetails";
+    args: {
+      specifier: string;
+      position: number;
+      name: string;
+      source?: string;
+      data?: unknown;
+    };
+  }
+
   interface GetCompletionsRequest extends BaseLanguageServerRequest {
     method: "getCompletions";
     specifier: string;
     position: number;
-    preferences: ts.UserPreferences;
+    preferences: ts.GetCompletionsAtPositionOptions;
   }
 
   interface GetDiagnosticsRequest extends BaseLanguageServerRequest {