diff --git a/1556.thousand-separator.js b/1556.thousand-separator.js
new file mode 100644
index 00000000..d7e6fda6
--- /dev/null
+++ b/1556.thousand-separator.js
@@ -0,0 +1,21 @@
+/* URL of this problem
+ * https://leetcode.com/problems/thousand-separator/description/
+ *
+ * @param {number} n
+ * @return {string}
+ */
+
+var thousandSeparator = function (n) {
+  let str = n.toString();
+  const SeparatatedStr = [];
+
+  // Extract the last 3 digits and add them to SeparatatedStr in an order by occurrence
+  while (str.length > 0) {
+    SeparatatedStr.unshift(str.substring(str.length - 3, str.length));
+    str = str.substring(0, str.length - 3);
+  }
+
+  return SeparatatedStr.join(".");
+};
+
+module.exports = thousandSeparator;
diff --git a/thousandSeparator.test.js b/thousandSeparator.test.js
new file mode 100644
index 00000000..dc9c24c9
--- /dev/null
+++ b/thousandSeparator.test.js
@@ -0,0 +1,13 @@
+const thousandSeparator = require("../jest-test/1556.thousand-separator");
+
+test("Return a string wihtout any separator dot", () => {
+  expect(thousandSeparator(987)).toBe("987");
+});
+
+test("Return a string seperated by dots", () => {
+  expect(thousandSeparator(1234)).toBe("1.234");
+});
+
+test("Return a string of 0s seperated by dots if the input n consists only of 0", () => {
+  expect(thousandSeparator(0000000)).toBe("0.000.000");
+});