diff --git a/CHANGES.md b/CHANGES.md
index 4528a14..7624338 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,5 @@
 # Changes Logs
 
-## v0.1.0
+## v0.1.1
 
-Nothing yet.
+- Fixed filter "|length".
diff --git a/package-lock.json b/package-lock.json
index f925f76..7b2eb1e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,5 +1,5 @@
 {
   "name": "@litert/typeguard",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "lockfileVersion": 1
 }
diff --git a/package.json b/package.json
index 513a19e..3485718 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@litert/typeguard",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "A type checking code \"JIT\" library.",
   "main": "dist/index.js",
   "scripts": {
diff --git a/sources/lang.javascript.ts b/sources/lang.javascript.ts
index 0cb8a4c..5256be2 100644
--- a/sources/lang.javascript.ts
+++ b/sources/lang.javascript.ts
@@ -119,7 +119,7 @@ implements Language {
         case FILTER_ON.LENGTH:
             ret.push(`${v} !== null`);
             ret.push(`${v} !== undefined`);
-            ret.push(`typeof ${v} === "number"`);
+            ret.push(`typeof ${v}.length === "number"`);
             v = `${v}.length`;
             break;
         case FILTER_ON.ARRAY_LENGTH: