fix: don't create new output channel after restart (#2722)

Author: jasonlyu123

packages/svelte-vscode/src/extension.ts

@@ -40,14 +40,25 @@ namespace TagCloseRequest {
     );
 }
 
-let lsApi: { getLS(): LanguageClient } | undefined;
+let lsApi:
+    | {
+          getLS(): LanguageClient;
+          restartLS(showNotification: boolean): Promise<void>;
+      }
+    | undefined;
 
 export function activate(context: ExtensionContext) {
     // The extension is activated on TS/JS/Svelte files because else it might be too late to configure the TS plugin:
     // If we only activate on Svelte file and the user opens a TS file first, the configuration command is issued too late.
     // We wait until there's a Svelte file open and only then start the actual language client.
     const tsPlugin = new TsPlugin(context);
 
+    context.subscriptions.push(
+        commands.registerCommand('svelte.restartLanguageServer', async () => {
+            await lsApi?.restartLS(true);
+        })
+    );
+
     if (workspace.textDocuments.some((doc) => doc.languageId === 'svelte')) {
         lsApi = activateSvelteLanguageServer(context);
         tsPlugin.askToEnable();
@@ -150,7 +161,10 @@ export function activateSvelteLanguageServer(context: ExtensionContext) {
         console.log('setting server runtime to', serverRuntime);
     }
 
+    // Manually create the output channel so that it'll be reused and won't lose focus during restarts
+    const outputChannel = window.createOutputChannel('Svelte', 'svelte');
     const clientOptions: LanguageClientOptions = {
+        outputChannel,
         documentSelector: [{ scheme: 'file', language: 'svelte' }],
         revealOutputChannelOn: RevealOutputChannelOn.Never,
         synchronize: {
@@ -187,7 +201,7 @@ export function activateSvelteLanguageServer(context: ExtensionContext) {
         }
     };
 
-    let ls = createLanguageServer(serverOptions, clientOptions);
+    const ls = createLanguageServer(serverOptions, clientOptions);
     ls.start().then(() => {
         const tagRequestor = (document: TextDocument, position: Position) => {
             const param = ls.code2ProtocolConverter.asTextDocumentPositionParams(
@@ -222,22 +236,15 @@ export function activateSvelteLanguageServer(context: ExtensionContext) {
         }
     });
 
-    context.subscriptions.push(
-        commands.registerCommand('svelte.restartLanguageServer', async () => {
-            await restartLS(true);
-        })
-    );
-
     let restartingLs = false;
     async function restartLS(showNotification: boolean) {
         if (restartingLs) {
             return;
         }
 
         restartingLs = true;
-        await ls.stop();
-        ls = createLanguageServer(serverOptions, clientOptions);
-        await ls.start();
+        outputChannel.clear();
+        await ls.restart();
         if (showNotification) {
             window.showInformationMessage('Svelte language server restarted.');
         }
@@ -325,7 +332,8 @@ export function activateSvelteLanguageServer(context: ExtensionContext) {
     });
 
     return {
-        getLS
+        getLS,
+        restartLS
     };
 }