diff --git a/package.json b/package.json
index d7c4750..4709b39 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@serverless-guru/logger",
-    "version": "1.0.3",
+    "version": "1.0.4",
     "description": "Common logger utility",
     "main": "./lib/cjs/index.js",
     "types": "./lib/cjs/index.d.ts",
diff --git a/src/index.ts b/src/index.ts
index 65437d5..49fe52d 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -64,13 +64,8 @@ class Logger {
             const arrayToLowerCase = (array: StringArray): StringArray => {
                 if (Array.isArray(array)) {
                     return array
-                        .map((el) => {
-                            if (typeof el === "string") {
-                                return el.toLowerCase();
-                            }
-                            return undefined;
-                        })
-                        .filter((el) => typeof el !== "undefined");
+                    .filter((el) => typeof el === "string")
+                    .map((el) => el.toLowerCase());
                 }
                 return [];
             };