diff --git a/src/server/languageProvider.ts b/src/server/languageProvider.ts
index 6667608..58a431d 100644
--- a/src/server/languageProvider.ts
+++ b/src/server/languageProvider.ts
@@ -166,13 +166,22 @@ export default class LanguageProvider {
   }
 
   public handles(resource: string, doc: TextDocument): boolean {
-    if (doc && this.description.modeIds.indexOf(doc.languageId) >= 0) {
+    if (doc && this.description.modeIds.includes(doc.languageId)) {
       return true
     }
-    const base = path.basename(Uri.parse(resource).fsPath)
+    return this.handlesConfigFile(Uri.parse(resource))
+  }
+
+  private handlesConfigFile(uri: Uri): boolean {
+    const base = path.basename(uri.fsPath)
     return !!base && (!!this.description.configFilePattern && this.description.configFilePattern.test(base))
   }
 
+  public handlesUri(resource: Uri): boolean {
+    const ext = path.extname(resource.path).slice(1).toLowerCase()
+    return this.description.standardFileExtensions.includes(ext) || this.handlesConfigFile(resource)
+  }
+
   private get id(): string { // tslint:disable-line
     return this.description.id
   }
diff --git a/src/server/typescriptServiceClientHost.ts b/src/server/typescriptServiceClientHost.ts
index 0305b25..9b575fe 100644
--- a/src/server/typescriptServiceClientHost.ts
+++ b/src/server/typescriptServiceClientHost.ts
@@ -2,7 +2,7 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
-import { disposeAll, languages, TextDocument, Uri, workspace } from 'coc.nvim'
+import { ConfigurationChangeEvent, disposeAll, languages, TextDocument, Uri, workspace } from 'coc.nvim'
 import { CancellationToken, Diagnostic, DiagnosticRelatedInformation, DiagnosticSeverity, DiagnosticTag, Disposable, Position, Range } from 'vscode-languageserver-protocol'
 import { flatten } from '../utils/arrays'
 import { PluginManager } from '../utils/plugins'
@@ -113,6 +113,7 @@ export default class TypeScriptServiceClientHost implements Disposable {
             diagnosticSource: 'ts-plugin',
             diagnosticLanguage: DiagnosticLanguage.TypeScript,
             diagnosticOwner: 'typescript',
+            standardFileExtensions: [],
             isExternal: true
           })
         } else {
@@ -129,6 +130,7 @@ export default class TypeScriptServiceClientHost implements Disposable {
           diagnosticSource: 'ts-plugin',
           diagnosticLanguage: DiagnosticLanguage.TypeScript,
           diagnosticOwner: 'typescript',
+          standardFileExtensions: [],
           isExternal: true
         })
       }
@@ -176,17 +178,20 @@ export default class TypeScriptServiceClientHost implements Disposable {
     return this.languagePerId.get(languageId)
   }
 
-  private configurationChanged(): void {
-    const config = workspace.getConfiguration('tsserver')
-    this.reportStyleCheckAsWarnings = config.get('reportStyleChecksAsWarnings', true)
+  private configurationChanged(e?: ConfigurationChangeEvent): void {
+    if (!e || e.affectsConfiguration('tsserver')) {
+      const config = workspace.getConfiguration('tsserver')
+      this.reportStyleCheckAsWarnings = config.get('reportStyleChecksAsWarnings', true)
+    }
   }
 
   public async findLanguage(uri: string): Promise<LanguageProvider> {
     try {
       let doc = this.client.getDocument(uri)
-      if (!doc) return undefined
       let languages = Array.from(this.languagePerId.values())
-      return languages.find(language => language.handles(uri, doc.textDocument))
+      // possible not opened
+      if (doc) return languages.find(language => language.handles(uri, doc.textDocument))
+      return languages.find(language => language.handlesUri(Uri.parse(uri)))
     } catch {
       return undefined
     }
diff --git a/src/server/utils/languageDescription.ts b/src/server/utils/languageDescription.ts
index 75cd1f9..c3a09af 100644
--- a/src/server/utils/languageDescription.ts
+++ b/src/server/utils/languageDescription.ts
@@ -13,6 +13,7 @@ export interface LanguageDescription {
   readonly isExternal?: boolean
   readonly diagnosticOwner: string
   readonly configFilePattern?: RegExp
+  readonly standardFileExtensions: ReadonlyArray<string>,
 }
 
 export const enum DiagnosticLanguage {
@@ -29,7 +30,13 @@ export const standardLanguageDescriptions: LanguageDescription[] = [
     languageModeIds.typescripttsx, languageModeIds.typescriptjsx],
     diagnosticLanguage: DiagnosticLanguage.TypeScript,
     configFile: 'tsconfig.json',
-    configFilePattern: /^tsconfig(\..*)?\.json$/gi
+    configFilePattern: /^tsconfig(\..*)?\.json$/gi,
+    standardFileExtensions: [
+      'ts',
+      'tsx',
+      'cts',
+      'mts'
+    ]
   },
   {
     id: 'javascript',
@@ -38,6 +45,14 @@ export const standardLanguageDescriptions: LanguageDescription[] = [
     modeIds: [languageModeIds.javascript, languageModeIds.javascriptreact, languageModeIds.javascriptjsx],
     diagnosticLanguage: DiagnosticLanguage.JavaScript,
     configFile: 'jsconfig.json',
-    configFilePattern: /^jsconfig(\..*)?\.json$/gi
+    configFilePattern: /^jsconfig(\..*)?\.json$/gi,
+    standardFileExtensions: [
+      'js',
+      'jsx',
+      'cjs',
+      'mjs',
+      'es6',
+      'pac',
+    ]
   }
 ]