feat(language-server): add tag folding and linked editing

packages/language-server/src/html-service.ts

@@ -77,6 +77,22 @@ export function htmlFoldingRanges(
     .map((range) => ({ startLine: range.startLine, endLine: range.endLine }));
 }
 
+/** Ranges of the opening and closing tag names, so renaming one renames both. */
+export function htmlLinkedEditingRanges(
+  document: TextDocument,
+  position: Position,
+): Array<{ start: Position; end: Position }> | null {
+  if (!isInsideHtml(document, offsetAt(document.text, position))) return null;
+
+  const virtual = htmlDocument(document);
+  const ranges = service.findLinkedEditingRanges(
+    virtual,
+    position,
+    service.parseHTMLDocument(virtual),
+  );
+  return ranges && ranges.length ? ranges : null;
+}
+
 /**
  * Detects `<Name attr="x" /` just before `position` and completes the `>`.
  *

packages/language-server/src/server.ts

@@ -19,7 +19,13 @@ import {
   htmlToWrn,
   type TextDocument,
 } from "./index.ts";
-import { htmlCompletions, htmlHover, mergeCompletions } from "./html-service.ts";
+import {
+  htmlCompletions,
+  htmlFoldingRanges,
+  htmlHover,
+  htmlLinkedEditingRanges,
+  mergeCompletions,
+} from "./html-service.ts";
 import { clearHtmlRegionCache } from "./html-regions.ts";
 
 type JsonRpc = { jsonrpc?: string; id?: number | string; method?: string; params?: any };
@@ -117,6 +123,8 @@ async function handle(message: JsonRpc): Promise<void> {
             triggerCharacters: ["<", "@", ":", ".", " ", "=", '"', "/"],
           },
           hoverProvider: true,
+          foldingRangeProvider: true,
+          linkedEditingRangeProvider: true,
           definitionProvider: true,
           referencesProvider: true,
           renameProvider: { prepareProvider: true },
@@ -223,6 +231,17 @@ async function handle(message: JsonRpc): Promise<void> {
       result(message.id, html ?? (document ? hover(document, params.position) : null));
       break;
     }
+    case "textDocument/foldingRange": {
+      const document = documents.get(params.textDocument.uri);
+      result(message.id, document ? htmlFoldingRanges(document) : []);
+      break;
+    }
+    case "textDocument/linkedEditingRange": {
+      const document = documents.get(params.textDocument.uri);
+      const ranges = document ? htmlLinkedEditingRanges(document, params.position) : null;
+      result(message.id, ranges ? { ranges } : null);
+      break;
+    }
     case "textDocument/definition": {
       const document = documents.get(params.textDocument.uri);
       result(message.id, document ? definitionLocation(document, params.position) : null);