Change the design to track addRoot and removeRoot

src/server/scriptInfo.ts

@@ -355,5 +355,9 @@ namespace ts.server {
         positionToLineOffset(position: number): ILineInfo {
             return this.textStorage.positionToLineOffset(position);
         }
+
+        public isJavaScript() {
+            return this.scriptKind === ScriptKind.JS || this.scriptKind === ScriptKind.JSX;
+        }
     }
 }