diff --git a/package-lock.json b/package-lock.json
index 11265b4..ccbc5ac 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -12,7 +12,7 @@
         "@types/codemirror": "0.0.109",
         "autoprefixer": "^10.4.0",
         "bulma": "^0.9.0",
-        "caniuse-lite": "^1.0.0",
+        "caniuse-lite": "^1.0.30001482",
         "codemirror": "^5.65.0",
         "commander": "^7.2.0",
         "core-js": "^3.29.1",
@@ -3278,9 +3278,9 @@
       }
     },
     "node_modules/caniuse-lite": {
-      "version": "1.0.30001474",
-      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001474.tgz",
-      "integrity": "sha512-iaIZ8gVrWfemh5DG3T9/YqarVZoYf0r188IjaGwx68j4Pf0SGY6CQkmJUIE+NZHkkecQGohzXmBGEwWDr9aM3Q==",
+      "version": "1.0.30001482",
+      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001482.tgz",
+      "integrity": "sha512-F1ZInsg53cegyjroxLNW9DmrEQ1SuGRTO1QlpA0o2/6OpQ0gFeDRoq1yFmnr8Sakn9qwwt9DmbxHB6w167OSuQ==",
       "funding": [
         {
           "type": "opencollective",
@@ -10047,9 +10047,9 @@
       "dev": true
     },
     "caniuse-lite": {
-      "version": "1.0.30001474",
-      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001474.tgz",
-      "integrity": "sha512-iaIZ8gVrWfemh5DG3T9/YqarVZoYf0r188IjaGwx68j4Pf0SGY6CQkmJUIE+NZHkkecQGohzXmBGEwWDr9aM3Q=="
+      "version": "1.0.30001482",
+      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001482.tgz",
+      "integrity": "sha512-F1ZInsg53cegyjroxLNW9DmrEQ1SuGRTO1QlpA0o2/6OpQ0gFeDRoq1yFmnr8Sakn9qwwt9DmbxHB6w167OSuQ=="
     },
     "chalk": {
       "version": "4.1.2",
diff --git a/package.json b/package.json
index 35b1fa1..54d681d 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "@types/codemirror": "0.0.109",
     "autoprefixer": "^10.4.0",
     "bulma": "^0.9.0",
-    "caniuse-lite": "^1.0.0",
+    "caniuse-lite": "^1.0.30001482",
     "codemirror": "^5.65.0",
     "commander": "^7.2.0",
     "core-js": "^3.29.1",
diff --git a/src/Language/TypeScript/ASTNode.ts b/src/Language/TypeScript/ASTNode.ts
index 75a8d33..c238f25 100644
--- a/src/Language/TypeScript/ASTNode.ts
+++ b/src/Language/TypeScript/ASTNode.ts
@@ -73,6 +73,9 @@ export class ASTNode implements ASTNodeInterface {
   }
 
   private isPossibleFauxClass() {
+    if (this.node.kind === ts.SyntaxKind.ArrowFunction) {
+      return false;
+    }
     if (this.node.kind === ts.SyntaxKind.FunctionDeclaration && (<ts.FunctionDeclaration>this.node).name) {
       return true;
     }
diff --git a/src/Language/TypeScript/__tests__/ASTNode.test.ts b/src/Language/TypeScript/__tests__/ASTNode.test.ts
index 8abfd19..fcb7e1f 100644
--- a/src/Language/TypeScript/__tests__/ASTNode.test.ts
+++ b/src/Language/TypeScript/__tests__/ASTNode.test.ts
@@ -14,7 +14,7 @@ describe('ASTNode', () => {
     });
   });
 
-  describe('.isFauxFunction()', () => {
+  describe('.isFauxClass()', () => {
     it('should checkable FauxClass structure', () => {
       const sourceFile = ts.createSourceFile(
         'dummy.ts',
@@ -29,6 +29,24 @@ describe('ASTNode', () => {
       expect(fauxClassStructure.isFauxClass()).toBe(true);
       expect(notFauxClassStructure.isFauxClass()).toBe(false);
     });
+
+    it('should returns false when arrow function.', () => {
+      const sourceFile = ts.createSourceFile(
+        'dummy.ts',
+        'const main = () => {return {hoge: () => {}}}; class A {}',
+        ts.ScriptTarget.ES2016,
+        true
+      );
+
+      const fauxClassStructure = new ASTNode(
+        (<ts.VariableStatement>sourceFile.statements[0]).declarationList.declarations[0].initializer!,
+        sourceFile
+      );
+      const notFauxClassStructure = new ASTNode(sourceFile.statements[1], sourceFile);
+
+      expect(fauxClassStructure.isFauxClass()).toBe(false);
+      expect(notFauxClassStructure.isFauxClass()).toBe(false);
+    });
   });
 
   describe('.isFunction()', () => {
diff --git a/src/Reporter/JSON/MetricsCalculator.ts b/src/Reporter/JSON/MetricsCalculator.ts
index d7c62d3..34dc3c4 100644
--- a/src/Reporter/JSON/MetricsCalculator.ts
+++ b/src/Reporter/JSON/MetricsCalculator.ts
@@ -33,28 +33,32 @@ export class MetricsCalculator {
       .toNumber();
   }
 
-  max<T extends MetricsValue>(identity: MetricsValueConstructor<T>): Metrics {
+  max<T extends MetricsValue>(identity: MetricsValueConstructor<T>): Metrics | null {
     return (
       this.metrics
         .filter((metrics) => metrics.hasMetricsValue(identity))
-        .reduce((max, metrics) =>
-          Number(max?.getMetricsByMetricsValue(identity) ?? -Infinity) >
-          Number(metrics.getMetricsByMetricsValue(identity))
-            ? max
-            : metrics
+        .reduce(
+          (max, metrics) =>
+            Number(max?.getMetricsByMetricsValue(identity) ?? -Infinity) >
+            Number(metrics.getMetricsByMetricsValue(identity))
+              ? max
+              : metrics,
+          <Metrics | null>null
         ) ?? null
     );
   }
 
-  min<T extends MetricsValue>(identity: MetricsValueConstructor<T>): Metrics {
+  min<T extends MetricsValue>(identity: MetricsValueConstructor<T>): Metrics | null {
     return (
       this.metrics
         .filter((metrics) => metrics.hasMetricsValue(identity))
-        .reduce((min, metrics) =>
-          Number(min?.getMetricsByMetricsValue(identity) ?? Infinity) <
-          Number(metrics.getMetricsByMetricsValue(identity))
-            ? min
-            : metrics
+        .reduce(
+          (min, metrics) =>
+            Number(min?.getMetricsByMetricsValue(identity) ?? Infinity) <
+            Number(metrics.getMetricsByMetricsValue(identity))
+              ? min
+              : metrics,
+          <Metrics | null>null
         ) ?? null
     );
   }
diff --git a/src/index.ts b/src/index.ts
index 2ee49a6..cfeeeeb 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -37,7 +37,7 @@ Fo  r HTML or CSV, specify the directory, and for JSON, specify the file.`
 
       const rootPath = fs.statSync(analyzedTarget).isDirectory() ? analyzedTarget : dirname(analyzedTarget);
       container.rebind<string>(Types.rootPath).toConstantValue(rootPath);
-      container.rebind<string | null>(Types.outputPath).toConstantValue(outputPath);
+      container.rebind<string | null>(Types.outputPath).toConstantValue(outputPath ?? '');
       container.rebind<RegExp>(Types.fileMatches).toConstantValue(matches);
       container.rebind<RegExp[]>(Types.fileExcludes).toConstantValue(excludes);