diff --git a/src/arrayMethodJoin.js b/src/arrayMethodJoin.js
index 3a62201c..67b6d7d8 100644
--- a/src/arrayMethodJoin.js
+++ b/src/arrayMethodJoin.js
@@ -1,11 +1,19 @@
-'use strict';
-
-/**
- * Implement method join
- */
+"use strict";
 function applyCustomJoin() {
-  [].__proto__.join2 = function(separator) {
-    // write code here
+  [].__proto__.join2 = function (separator = ",") {
+    let str = "";
+
+    for (let i = 0; i <= this.length; i++) {
+      if (this[i] !== null && this[i] !== undefined) {
+        str += this[i];
+      }
+
+      if (i < this.length - 1) {
+        str += separator;
+      }
+    }
+
+    return str;
   };
 }