diff --git a/2138.divide-a-string-into-groups-of-size-k.js b/2138.divide-a-string-into-groups-of-size-k.js
new file mode 100644
index 00000000..376070a9
--- /dev/null
+++ b/2138.divide-a-string-into-groups-of-size-k.js
@@ -0,0 +1,28 @@
+/* URL of this problem
+ * https://leetcode.com/problems/divide-a-string-into-groups-of-size-k/description/
+ *
+ * @param {string} s
+ * @param {number} k
+ * @param {character} fill
+ * @return {string[]}
+ */
+
+var divideString = function(s, k, fill) {
+    const Divided = [];
+    const LastGroupLen = s.length % k;
+
+    for (let i = 0; i < s.length; i += k) {
+        const Substr = s.substring(i, i + k);
+
+        Divided.push(Substr);
+    }
+    // A character fill is used to complete the group
+    // if the length of the last group does not have k characters remaining.
+    if (LastGroupLen > 0 && LastGroupLen < k) {
+        Divided[Divided.length -1] += fill.repeat(k - LastGroupLen);
+    }
+
+    return Divided;
+};
+
+module.exports = divideString;
\ No newline at end of file
diff --git a/divideString.test.js b/divideString.test.js
new file mode 100644
index 00000000..106ddbe1
--- /dev/null
+++ b/divideString.test.js
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+const divideString = require("./2138.divide-a-string-into-groups-of-size-k");
+
+test("Return the divided groups, each of them has exactyly k characters", () => {
+    expect(divideString("abcdefghi", 3, "x")).toEqual(["abc","def","ghi"]);
+});
+
+test("Return the divided groups, every group of them but the last one has exactly k characters", () => {
+    expect(divideString("abcdefghij", 3, "x")).toEqual(["abc","def","ghi","jxx"]);
+});
+
+test("Return the divided groups, the last group of them is not filled with the character fill if the character fill is empty", () => {
+    expect(divideString("abcdefghij", 3, "")).toEqual(["abc","def","ghi","j"]);
+});