Add support for Format Document action

index.js

@@ -1,7 +1,13 @@
 'use strict';
 
-const { LanguageClient, SettingMonitor, ExecuteCommandRequest } = require('vscode-languageclient');
-const { workspace, commands: Commands, window: Window } = require('vscode');
+const {
+	LanguageClient,
+	SettingMonitor,
+	ExecuteCommandRequest,
+	DocumentFormattingRequest,
+	TextDocumentIdentifier,
+} = require('vscode-languageclient');
+const { workspace, commands: Commands, window: Window, languages: Languages } = require('vscode');
 
 /**
  * @typedef {import('vscode').ExtensionContext} ExtensionContext
@@ -37,6 +43,69 @@ exports.activate = ({ subscriptions }) => {
 		},
 	);
 
+	client.onReady().then(() => {
+		/**
+		 * Map of registered formatters by language ID.
+		 * @type {Map<string, { dispose(): any }>}
+		 */
+		const registeredFormatters = new Map();
+
+		client.onNotification('stylelint/languageIdsAdded', (/** @type {string[]} */ langIds) => {
+			for (const langId of langIds) {
+				// Avoid registering another formatter if we already registered one for the same language ID.
+				if (registeredFormatters.has(langId)) {
+					return;
+				}
+
+				const formatter = Languages.registerDocumentFormattingEditProvider(langId, {
+					provideDocumentFormattingEdits(textDocument, options) {
+						const params = {
+							textDocument: TextDocumentIdentifier.create(textDocument.uri.toString()),
+							options, // Editor formatting options, overriden by stylelint config.
+						};
+
+						// Request that the language server formats the document.
+						return client
+							.sendRequest(DocumentFormattingRequest.type, params)
+							.then(undefined, () => {
+								Window.showErrorMessage(
+									'Failed to format the document using stylelint. Please consider opening an issue with steps to reproduce.',
+								);
+
+								return null;
+							});
+					},
+				});
+
+				// Keep track of the new formatter.
+				registeredFormatters.set(langId, formatter);
+			}
+		});
+
+		client.onNotification('stylelint/languageIdsRemoved', (/** @type {string[]} */ langIds) => {
+			for (const langId of langIds) {
+				const formatter = registeredFormatters.get(langId);
+
+				if (!formatter) {
+					return;
+				}
+
+				// Unregisters formatter.
+				formatter.dispose();
+				registeredFormatters.delete(langId);
+			}
+		});
+
+		// Make sure that formatters are disposed when extension is unloaded.
+		subscriptions.push({
+			dispose() {
+				for (const formatter of registeredFormatters.values()) {
+					formatter.dispose();
+				}
+			},
+		});
+	});
+
 	subscriptions.push(
 		Commands.registerCommand('stylelint.executeAutofix', async () => {
 			const textEditor = Window.activeTextEditor;

server.js

@@ -245,10 +245,36 @@ async function validate(document) {
 
 /**
  * @param {TextDocument} document
+ * @param {import('vscode-languageserver').FormattingOptions?} formattingOptions Formatting options to use.
+ * Overriden by stylelint configuration.
  * @returns {Promise<TextEdit[]>}
  */
-async function getFixes(document) {
-	const options = await buildStylelintOptions(document, { fix: true });
+async function getFixes(document, formattingOptions = null) {
+	/** @type {Partial<import('stylelint').LinterOptions>} */
+	const baseOptions = { fix: true };
+
+	// If formatting options were provided, translate them to their corresponding rules.
+	// NOTE: There is no equivalent rule for trimFinalNewlines, so it is not respected.
+	if (formattingOptions) {
+		const { insertSpaces, tabSize, insertFinalNewline, trimTrailingWhitespace } = formattingOptions;
+
+		/** @type {Record<string, any>} */
+		const rules = {
+			indentation: [insertSpaces ? tabSize : 'tab'],
+		};
+
+		if (insertFinalNewline !== undefined) {
+			rules['no-missing-end-of-source-newline'] = insertFinalNewline;
+		}
+
+		if (trimTrailingWhitespace !== undefined) {
+			rules['no-eol-whitespace'] = trimTrailingWhitespace;
+		}
+
+		baseOptions.config = { rules };
+	}
+
+	const options = await buildStylelintOptions(document, baseOptions);
 
 	try {
 		const result = await stylelintVSCode(
@@ -319,6 +345,7 @@ connection.onInitialize(() => {
 			executeCommandProvider: {
 				commands: [CommandIds.applyAutoFix],
 			},
+			documentFormattingProvider: true,
 			codeActionProvider: { codeActionKinds: [CodeActionKind.QuickFix, StylelintSourceFixAll] },
 			completionProvider: {},
 		},
@@ -350,6 +377,16 @@ connection.onDidChangeConfiguration(({ settings }) => {
 		clearDiagnostics(document);
 	}
 
+	if (removeLanguages.length > 0) {
+		connection.sendNotification('stylelint/languageIdsRemoved', removeLanguages);
+	}
+
+	const addLanguages = validateLanguages.filter((lang) => !oldValidateLanguages.includes(lang));
+
+	if (addLanguages.length > 0) {
+		connection.sendNotification('stylelint/languageIdsAdded', addLanguages);
+	}
+
 	validateAll();
 });
 connection.onDidChangeWatchedFiles(validateAll);
@@ -400,6 +437,22 @@ connection.onExecuteCommand(async (params) => {
 
 	return {};
 });
+connection.onDocumentFormatting((params) => {
+	if (!params.textDocument) {
+		return null;
+	}
+
+	/** @type { { uri: string } } */
+	const identifier = params.textDocument;
+	const uri = identifier.uri;
+	const document = documents.get(uri);
+
+	if (!document || !isValidateOn(document)) {
+		return null;
+	}
+
+	return getFixes(document, params.options);
+});
 connection.onCodeAction(async (params) => {
 	const only = params.context.only !== undefined ? params.context.only[0] : undefined;
 	const isSource = only === CodeActionKind.Source;

test/ws-formatter-test/.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+	"[css]": {
+		"editor.defaultFormatter": "stylelint.vscode-stylelint"
+	}
+}

test/ws-formatter-test/index.js

@@ -0,0 +1,41 @@
+'use strict';
+
+const fs = require('fs/promises');
+const path = require('path');
+
+const pWaitFor = require('p-wait-for');
+const test = require('tape');
+const { extensions, workspace, Uri, commands, window } = require('vscode');
+
+const run = () =>
+	test('vscode-stylelint', async (t) => {
+		const expectedCss = await fs.readFile(path.resolve(__dirname, 'test.expected.css'), 'utf8');
+
+		await commands.executeCommand('vscode.openFolder', Uri.file(__dirname));
+
+		const vscodeStylelint = extensions.getExtension('stylelint.vscode-stylelint');
+
+		// Open the './test.input.css' file.
+		const cssDocument = await workspace.openTextDocument(path.resolve(__dirname, 'test.input.css'));
+
+		await window.showTextDocument(cssDocument);
+
+		await commands.executeCommand('editor.action.indentUsingTabs', {
+			tabSize: 4,
+			indentSize: 4,
+			insertSpaces: false,
+		});
+
+		await pWaitFor(() => vscodeStylelint.isActive, { timeout: 2000 });
+
+		await commands.executeCommand('editor.action.formatDocument');
+
+		t.equal(cssDocument.getText(), expectedCss, 'should format document using formatting options.');
+
+		t.end();
+	});
+
+exports.run = (root, done) => {
+	test.onFinish(done);
+	run();
+};

test/ws-formatter-test/test.expected.css

@@ -0,0 +1,3 @@
+a {
+	color: red;
+}

test/ws-formatter-test/test.input.css

@@ -0,0 +1,3 @@
+a {
+  color: red;
+}