diff --git a/bin/utils.cjs b/bin/utils.cjs
index 345e4b3..61abc58 100644
--- a/bin/utils.cjs
+++ b/bin/utils.cjs
@@ -142,11 +142,11 @@ class WSSharedDoc extends Y.Doc {
     this.awareness.on('update', awarenessChangeHandler)
     this.on('update', /** @type {any} */ (updateHandler))
     if (isCallbackSet) {
-      this.on('update', debounce(
+      this.on('update', /** @type {any} */ (debounce(
         callbackHandler,
         CALLBACK_DEBOUNCE_WAIT,
         { maxWait: CALLBACK_DEBOUNCE_MAXWAIT }
-      ))
+      )))
     }
     this.whenInitialized = contentInitializor(this)
   }
@@ -233,7 +233,7 @@ const closeConn = (doc, conn) => {
 
 /**
  * @param {WSSharedDoc} doc
- * @param {any} conn
+ * @param {import('ws').WebSocket} conn
  * @param {Uint8Array} m
  */
 const send = (doc, conn, m) => {
@@ -241,7 +241,7 @@ const send = (doc, conn, m) => {
     closeConn(doc, conn)
   }
   try {
-    conn.send(m, /** @param {any} err */ err => { err != null && closeConn(doc, conn) })
+    conn.send(m, {}, err => { err != null && closeConn(doc, conn) })
   } catch (e) {
     closeConn(doc, conn)
   }
@@ -250,11 +250,11 @@ const send = (doc, conn, m) => {
 const pingTimeout = 30000
 
 /**
- * @param {any} conn
- * @param {any} req
+ * @param {import('ws').WebSocket} conn
+ * @param {import('http').IncomingMessage} req
  * @param {any} opts
  */
-exports.setupWSConnection = (conn, req, { docName = req.url.slice(1).split('?')[0], gc = true } = {}) => {
+exports.setupWSConnection = (conn, req, { docName = (req.url || '').slice(1).split('?')[0], gc = true } = {}) => {
   conn.binaryType = 'arraybuffer'
   // get doc, initialize if it does not exist yet
   const doc = getYDoc(docName, gc)
diff --git a/package-lock.json b/package-lock.json
index 87a80ac..af737dc 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -18,6 +18,7 @@
         "y-websocket-server": "bin/server.cjs"
       },
       "devDependencies": {
+        "@types/lodash.debounce": "^4.0.9",
         "@types/node": "^18.15.0",
         "@types/ws": "^8.5.10",
         "rollup": "^3.19.1",
@@ -41,6 +42,21 @@
         "yjs": "^13.5.6"
       }
     },
+    "node_modules/@types/lodash": {
+      "version": "4.17.0",
+      "resolved": "https://registry.npmjs.org/@types/lodash/-/lodash-4.17.0.tgz",
+      "integrity": "sha512-t7dhREVv6dbNj0q17X12j7yDG4bD/DHYX7o5/DbDxobP0HnGPgpRz2Ej77aL7TZT3DSw13fqUTj8J4mMnqa7WA==",
+      "dev": true
+    },
+    "node_modules/@types/lodash.debounce": {
+      "version": "4.0.9",
+      "resolved": "https://registry.npmjs.org/@types/lodash.debounce/-/lodash.debounce-4.0.9.tgz",
+      "integrity": "sha512-Ma5JcgTREwpLRwMM+XwBR7DaWe96nC38uCBDFKZWbNKD+osjVzdpnUSwBcqCptrp16sSOLBAUb50Car5I0TCsQ==",
+      "dev": true,
+      "dependencies": {
+        "@types/lodash": "*"
+      }
+    },
     "node_modules/@types/node": {
       "version": "18.15.0",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-18.15.0.tgz",
diff --git a/package.json b/package.json
index ad41ea0..99a4ace 100644
--- a/package.json
+++ b/package.json
@@ -64,6 +64,7 @@
     "y-protocols": "^1.0.5"
   },
   "devDependencies": {
+    "@types/lodash.debounce": "^4.0.9",
     "@types/node": "^18.15.0",
     "@types/ws": "^8.5.10",
     "rollup": "^3.19.1",