(feat) Fallback ts/js watcher for clients which don't support didChan…

…geWatchedFiles (#841)

When a language server client doesn't support didChangeWatchedFiles. Initialize our own fallback file watcher.
This should fix the ts, js file doesn't get updated issue on the sublime text.

packages/language-server/src/lib/FallbackWatcher.ts

@@ -0,0 +1,44 @@
+import { FSWatcher, watch } from 'chokidar';
+import { join } from 'path';
+import { DidChangeWatchedFilesParams, FileChangeType, FileEvent } from 'vscode-languageserver';
+import { pathToUrl } from '../utils';
+
+type DidChangeHandler = (para: DidChangeWatchedFilesParams) => void;
+
+export class FallbackWatcher {
+    private readonly watcher: FSWatcher;
+    private readonly callbacks: DidChangeHandler[] = [];
+
+    constructor(glob: string, workspacePaths: string[]) {
+        this.watcher = watch(workspacePaths.map((workspacePath) => join(workspacePath, glob)));
+
+        this.watcher
+            .on('add', (path) => this.callback(path, FileChangeType.Created))
+            .on('unlink', (path) => this.callback(path, FileChangeType.Deleted))
+            .on('change', (path) => this.callback(path, FileChangeType.Changed));
+    }
+
+    private convert(path: string, type: FileChangeType): DidChangeWatchedFilesParams {
+        const event: FileEvent = {
+            type,
+            uri: pathToUrl(path)
+        };
+
+        return {
+            changes: [event]
+        };
+    }
+
+    private callback(path: string, type: FileChangeType) {
+        const para = this.convert(path, type);
+        this.callbacks.forEach((callback) => callback(para));
+    }
+
+    onDidChangeWatchedFiles(callback: DidChangeHandler) {
+        this.callbacks.push(callback);
+    }
+
+    dispose() {
+        this.watcher.close();
+    }
+}

packages/language-server/src/server.ts

@@ -14,7 +14,8 @@ import {
     TextDocumentSyncKind,
     WorkspaceEdit,
     SemanticTokensRequest,
-    SemanticTokensRangeRequest
+    SemanticTokensRangeRequest,
+    DidChangeWatchedFilesParams
 } from 'vscode-languageserver';
 import { IPCMessageReader, IPCMessageWriter, createConnection } from 'vscode-languageserver/node';
 import { DiagnosticsManager } from './lib/DiagnosticsManager';
@@ -31,7 +32,8 @@ import {
     TypeScriptPlugin,
     OnWatchFileChangesPara
 } from './plugins';
-import { urlToPath } from './utils';
+import { isNotNullOrUndefined, urlToPath } from './utils';
+import { FallbackWatcher } from './lib/FallbackWatcher';
 
 namespace TagCloseRequest {
     export const type: RequestType<
@@ -85,6 +87,7 @@ export function startServer(options?: LSOptions) {
     const configManager = new LSConfigManager();
     const pluginHost = new PluginHost(docManager);
     let sveltePlugin: SveltePlugin = undefined as any;
+    let watcher: FallbackWatcher | undefined;
 
     connection.onInitialize((evt) => {
         const workspaceUris = evt.workspaceFolders?.map((folder) => folder.uri.toString()) ?? [
@@ -95,6 +98,12 @@ export function startServer(options?: LSOptions) {
             Logger.error('No workspace path set');
         }
 
+        if (!evt.capabilities.workspace?.didChangeWatchedFiles) {
+            const workspacePaths = workspaceUris.map(urlToPath).filter(isNotNullOrUndefined);
+            watcher = new FallbackWatcher('**/*.{ts,js}', workspacePaths);
+            watcher.onDidChangeWatchedFiles(onDidChangeWatchedFiles);
+        }
+
         configManager.update(evt.initializationOptions?.config || {});
         configManager.updateTsJsUserPreferences(evt.initializationOptions?.typescriptConfig || {});
         configManager.updateEmmetConfig(evt.initializationOptions?.emmetConfig || {});
@@ -199,6 +208,10 @@ export function startServer(options?: LSOptions) {
         };
     });
 
+    connection.onExit(() => {
+        watcher?.dispose();
+    });
+
     connection.onRenameRequest((req) =>
         pluginHost.rename(req.textDocument, req.position, req.newName)
     );
@@ -285,7 +298,9 @@ export function startServer(options?: LSOptions) {
     );
 
     const updateAllDiagnostics = _.debounce(() => diagnosticsManager.updateAll(), 1000);
-    connection.onDidChangeWatchedFiles((para) => {
+
+    connection.onDidChangeWatchedFiles(onDidChangeWatchedFiles);
+    function onDidChangeWatchedFiles(para: DidChangeWatchedFilesParams) {
         const onWatchFileChangesParas = para.changes
             .map((change) => ({
                 fileName: urlToPath(change.uri),
@@ -296,7 +311,8 @@ export function startServer(options?: LSOptions) {
         pluginHost.onWatchFileChanges(onWatchFileChangesParas);
 
         updateAllDiagnostics();
-    });
+    }
+
     connection.onDidSaveTextDocument(updateAllDiagnostics);
     connection.onNotification('$/onDidChangeTsOrJsFile', async (e: any) => {
         const path = urlToPath(e.uri);