diff --git a/src/server/project.ts b/src/server/project.ts
index aadae734ee4..524b6c4d28d 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -936,9 +936,9 @@ namespace ts.server {
     export class ConfiguredProject extends Project {
         private typeAcquisition: TypeAcquisition;
         private projectFileWatcher: FileWatcher;
-        private directoryWatcher: FileWatcher;
-        private directoriesWatchedForWildcards: Map<FileWatcher>;
-        private typeRootsWatchers: FileWatcher[];
+        private directoryWatcher: FileWatcher | undefined;
+        private directoriesWatchedForWildcards: Map<FileWatcher> | undefined;
+        private typeRootsWatchers: FileWatcher[] | undefined;
         readonly canonicalConfigFilePath: NormalizedPath;
 
         private plugins: PluginModule[] = [];