typescript-language-server · rchl · Oct 31, 2025 · Oct 30, 2025 · Oct 30, 2025 · Oct 30, 2025
diff --git a/README.md b/README.md
@@ -23,6 +23,7 @@
     - [Code Lenses \(`textDocument/codeLens`\)](#code-lenses-textdocumentcodelens)
     - [Inlay hints \(`textDocument/inlayHint`\)](#inlay-hints-textdocumentinlayhint)
     - [TypeScript Version Notification](#typescript-version-notification)
+    - [Workspace Configuration request for formatting settings](#workspace-configuration-request-for-formatting-settings)
 - [Development](#development)
     - [Build](#build)
     - [Dev](#dev)
@@ -108,89 +109,104 @@ Most of the time, you'll execute commands with arguments retrieved from another
 
 #### Go to Source Definition
 
-- Request:
-    ```ts
-    {
-        command: `_typescript.goToSourceDefinition`
-        arguments: [
-            lsp.DocumentUri,  // String URI of the document
-            lsp.Position,     // Line and character position (zero-based)
-        ]
-    }
-    ```
-- Response:
-    ```ts
-    lsp.Location[] | null
-    ```
+Request:
+
+```ts
+{
+    command: '_typescript.goToSourceDefinition'
+    arguments: [
+        lsp.DocumentUri,  // String URI of the document
+        lsp.Position,     // Line and character position (zero-based)
+    ]
+}
+```
+
+Response:
+
+```ts
+lsp.Location[] | null
+```
 
 (This command is supported from Typescript 4.7.)
 
 #### Apply Refactoring
 
-- Request:
-    ```ts
-    {
-        command: `_typescript.applyRefactoring`
-        arguments: [
-            tsp.GetEditsForRefactorRequestArgs,
-        ]
-    }
-    ```
-- Response:
-    ```ts
-    void
-    ```
+Request:
+
+```ts
+{
+    command: '_typescript.applyRefactoring'
+    arguments: [
+        tsp.GetEditsForRefactorRequestArgs,
+    ]
+}
+```
+
+Response:
+
+```ts
+void
+```
 
 #### Organize Imports
 
-- Request:
-    ```ts
-    {
-        command: `_typescript.organizeImports`
-        arguments: [
-            // The "skipDestructiveCodeActions" argument is supported from Typescript 4.4+
-            [string] | [string, { skipDestructiveCodeActions?: boolean }],
-        ]
-    }
-    ```
-- Response:
-    ```ts
-    void
-    ```
+Request:
+
+```ts
+{
+    command: '_typescript.organizeImports'
+    arguments: [
+        // The "skipDestructiveCodeActions" argument is supported from Typescript 4.4+
+        [string] | [string, { skipDestructiveCodeActions?: boolean }],
+    ]
+}
+```
+
+Response:
+
+```ts
+void
+```
 
 #### Rename File
 
-- Request:
-    ```ts
-    {
-        command: `_typescript.applyRenameFile`
-        arguments: [
-            { sourceUri: string; targetUri: string; },
-        ]
-    }
-    ```
-- Response:
-    ```ts
-    void
-    ```
+Request:
+
+```ts
+{
+    command: '_typescript.applyRenameFile'
+    arguments: [
+        { sourceUri: string; targetUri: string; },
+    ]
+}
+```
+
+Response:
+
+```ts
+void
+```
 
 #### Send Tsserver Command
 
-- Request:
-    ```ts
-    {
-        command: `typescript.tsserverRequest`
-        arguments: [
-            string,       // command
-            any,          // command arguments in a format that the command expects
-            ExecuteInfo,  // configuration object used for the tsserver request (see below)
-        ]
-    }
-    ```
-- Response:
-    ```ts
-    any
-    ```
+Request:
+
+```ts
+{
+    command: 'typescript.tsserverRequest'
+    arguments: [
+        string,       // command
+        any,          // command arguments in a format that the command expects
+        ExecuteInfo,  // configuration object used for the tsserver request (see below)
+    ]
+}
+```
+
+Response:
+
+```ts
+any
+```
 
 The `ExecuteInfo` object is defined as follows:
 
@@ -205,17 +221,20 @@ type ExecuteInfo = {
 
 #### Configure plugin
 
-- Request:
-    ```ts
-    {
-        command: `_typescript.configurePlugin`
-        arguments: [pluginName: string, configuration: any]
-    }
-    ```
-- Response:
-    ```ts
-    void
-    ```
+Request:
+
+```ts
+{
+    command: '_typescript.configurePlugin'
+    arguments: [pluginName: string, configuration: any]
+}
+```
+
+Response:
+
+```ts
+void
+```
 
 ### Code Lenses (`textDocument/codeLens`)
 
@@ -275,6 +294,18 @@ The `$/typescriptVersion` notification params include two properties:
  - `version` - a semantic version (for example `4.8.4`)
  - `source` - a string specifying whether used TypeScript version comes from the local workspace (`workspace`), is explicitly specified through a `initializationOptions.tsserver.path` setting (`user-setting`) or was bundled with the server (`bundled`)
 
+
+### Workspace Configuration request for formatting settings
+
+Server asks the client for file-specific configuration options (`tabSize` and `insertSpaces`) that are required by `tsserver` to properly format the file edits when for example using "Organize imports" or performing other file modifications. Those options have to be dynamically provided by the client/editor since the values can differ for each file. For this reason server sends a `workspace/configuration` request with `scopeUri` equal to file's URI and `section` equal to `formattingOptions`. The client is expected to return a configuration that includes the following properties:
+
+```js
+{
+    "tabSize": number
+    "insertSpaces": boolean
+}
+```
+
 ## Development
 
 ### Build

diff --git a/src/features/fileConfigurationManager.ts b/src/features/fileConfigurationManager.ts
@@ -17,6 +17,7 @@ import { CommandTypes, ModuleKind, ScriptTarget, type ts, type TypeScriptInitial
 import { ITypeScriptServiceClient } from '../typescriptService.js';
 import { isTypeScriptDocument } from '../configuration/languageIds.js';
 import { LspDocument } from '../document.js';
+import type { LspClient } from '../lsp-client.js';
 import API from '../utils/api.js';
 import { equals } from '../utils/objects.js';
 import { ResourceMap } from '../utils/resourceMap.js';
@@ -147,6 +148,7 @@ export default class FileConfigurationManager {
 
     public constructor(
         private readonly client: ITypeScriptServiceClient,
+        private readonly lspClient: LspClient,
         onCaseInsensitiveFileSystem: boolean,
     ) {
         this.formatOptions = new ResourceMap(undefined, { onCaseInsensitiveFileSystem });
@@ -208,12 +210,22 @@ export default class FileConfigurationManager {
         document: LspDocument,
         token?: lsp.CancellationToken,
     ): Promise<void> {
-        return this.ensureConfigurationOptions(document, undefined, token);
+        const formattingOptions = await this.getFormattingOptions(document);
+        return this.ensureConfigurationOptions(document, formattingOptions, token);
+    }
+
+    private async getFormattingOptions(document: LspDocument): Promise<Partial<lsp.FormattingOptions>> {
+        const formatConfiguration = await this.lspClient.getWorkspaceConfiguration<Partial<lsp.FormattingOptions> | undefined>(document.uri.toString(), 'formattingOptions') || {};
+
+        return {
+            tabSize: typeof formatConfiguration.tabSize === 'number' ? formatConfiguration.tabSize : undefined,
+            insertSpaces: typeof formatConfiguration.insertSpaces === 'boolean' ? formatConfiguration.insertSpaces : undefined,
+        };
     }
 
     public async ensureConfigurationOptions(
         document: LspDocument,
-        options?: lsp.FormattingOptions,
+        options?: Partial<lsp.FormattingOptions>,
         token?: lsp.CancellationToken,
     ): Promise<void> {
         const currentOptions = this.getFileOptions(document, options);
@@ -260,7 +272,7 @@ export default class FileConfigurationManager {
 
     private getFileOptions(
         document: LspDocument,
-        options?: lsp.FormattingOptions,
+        options?: Partial<lsp.FormattingOptions>,
     ): FileConfiguration {
         return {
             formatOptions: this.getFormatOptions(document, options),
@@ -270,7 +282,7 @@ export default class FileConfigurationManager {
 
     private getFormatOptions(
         document: LspDocument,
-        formattingOptions?: lsp.FormattingOptions,
+        formattingOptions?: Partial<lsp.FormattingOptions>,
     ): ts.server.protocol.FormatCodeSettings {
         const workspacePreferences = this.getWorkspacePreferencesForFile(document);
 

diff --git a/src/lsp-client.ts b/src/lsp-client.ts
@@ -24,6 +24,7 @@ export interface LspClient {
     applyWorkspaceEdit(args: lsp.ApplyWorkspaceEditParams): Promise<lsp.ApplyWorkspaceEditResult>;
     rename(args: lsp.TextDocumentPositionParams): Promise<any>;
     sendNotification<P>(type: lsp.NotificationType<P>, params: P): Promise<void>;
+    getWorkspaceConfiguration<R = unknown>(scopeUri: string, section: string): Promise<R>;
 }
 
 // Hack around the LSP library that makes it otherwise impossible to differentiate between Null and Client-initiated reporter.
@@ -66,6 +67,10 @@ export class LspClientImpl implements LspClient {
         this.connection.sendNotification(lsp.LogMessageNotification.type, args);
     }
 
+    async getWorkspaceConfiguration<R = unknown>(scopeUri: string, section: string): Promise<R> {
+        return await this.connection.workspace.getConfiguration({ scopeUri, section }) as R;
+    }
+
     async applyWorkspaceEdit(params: lsp.ApplyWorkspaceEditParams): Promise<lsp.ApplyWorkspaceEditResult> {
         return this.connection.workspace.applyEdit(params);
     }

diff --git a/src/lsp-server.ts b/src/lsp-server.ts
@@ -65,7 +65,7 @@ export class LspServer {
     constructor(private options: LspServerConfiguration) {
         this.logger = new PrefixingLogger(options.logger, '[lspserver]');
         this.tsClient = new TsClient(onCaseInsensitiveFileSystem(), this.logger, options.lspClient);
-        this.fileConfigurationManager = new FileConfigurationManager(this.tsClient, onCaseInsensitiveFileSystem());
+        this.fileConfigurationManager = new FileConfigurationManager(this.tsClient, this.options.lspClient, onCaseInsensitiveFileSystem());
         this.commandManager = new CommandManager();
         this.diagnosticsManager = new DiagnosticsManager(
             diagnostics => this.options.lspClient.publishDiagnostics(diagnostics),
@@ -816,15 +816,19 @@ export class LspServer {
                     skipDestructiveCodeActions = documentHasErrors;
                     mode = OrganizeImportsMode.SortAndCombine;
                 }
-                const response = await this.tsClient.interruptGetErr(() => this.tsClient.execute(
-                    CommandTypes.OrganizeImports,
-                    {
-                        scope: { type: 'file', args: fileRangeArgs },
-                        // Deprecated in 4.9; `mode` takes priority.
-                        skipDestructiveCodeActions,
-                        mode,
-                    },
-                    token));
+                const response = await this.tsClient.interruptGetErr(async () => {
+                    await this.fileConfigurationManager.ensureConfigurationForDocument(document, token);
+
+                    return this.tsClient.execute(
+                        CommandTypes.OrganizeImports,
+                        {
+                            scope: { type: 'file', args: fileRangeArgs },
+                            // Deprecated in 4.9; `mode` takes priority.
+                            skipDestructiveCodeActions,
+                            mode,
+                        },
+                        token);
+                });
                 if (response.type === 'response' && response.body) {
                     actions.push(...provideOrganizeImports(command, response, this.tsClient));
                 }

diff --git a/src/test-utils.ts b/src/test-utils.ts
@@ -191,6 +191,10 @@ export class TestLspClient implements LspClient {
     sendNotification<P>(_type: lsp.NotificationType<P>, _params: P): Promise<void> {
         throw new Error('unsupported');
     }
+
+    async getWorkspaceConfiguration(_scopeUri: string, _section: string): Promise<any> {
+        return Promise.resolve(undefined);
+    }
 }
 
 export class TestLspServer extends LspServer {