diff --git a/lib/messageFormatFactory.js b/lib/messageFormatFactory.js
index 441fb56..1583c69 100644
--- a/lib/messageFormatFactory.js
+++ b/lib/messageFormatFactory.js
@@ -3,13 +3,13 @@ const formatDate = require('./formatDate')
 const colorizerFactory = require('pino-pretty').colorizerFactory
 
 const messageFormatFactory = (levels, colors, useColors) => {
-  const customColors =
-    colors != null
-      ? Object.entries(colors).reduce((colors, [level, color]) => {
-        colors.push([level, color])
-        return colors
-      }, [])
-      : undefined
+  let customColors
+  if (colors !== null) {
+    customColors = []
+    for (const entry of Object.entries(colors)) {
+      customColors.push(entry)
+    }
+  }
   const colorizer = colorizerFactory(useColors, customColors)
 
   const levelLookUp = {