Implement the solution for reverse integer problem

Author: somekindofwallflower

Diff for: 03_integer_reverse/index.js

@@ -0,0 +1,26 @@
+// --- Directions
+// Given an integer, return an integer that is the reverse
+// ordering of numbers.
+// --- Examples
+//   reverseInt(15) === 51
+//   reverseInt(981) === 189
+//   reverseInt(500) === 5
+//   reverseInt(-15) === -51
+//   reverseInt(-90) === -9
+
+// Tips to solve the problem
+// - Convert number to string by using toString function
+// - Check if it is a sign number or not by using Math.sign() function.
+// - Convert string to number by using parseInt method
+
+function reverseInt(n) {
+    const reversed = n
+        .toString()
+        .split('')
+        .reverse()
+        .join('');
+    return parseInt(reversed) * Math.sign(n);
+}
+
+
+module.exports = reverseInt;

Diff for: 03_integer_reverse/test.js

@@ -0,0 +1,23 @@
+const reverseInt = require('./index');
+
+test('ReverseInt function exists', () => {
+    expect(reverseInt).toBeDefined();
+});
+
+test('ReverseInt handles 0 as an input', () => {
+    expect(reverseInt(0)).toEqual(0);
+});
+
+test('ReverseInt flips a positive number', () => {
+    expect(reverseInt(5)).toEqual(5);
+    expect(reverseInt(15)).toEqual(51);
+    expect(reverseInt(90)).toEqual(9);
+    expect(reverseInt(2359)).toEqual(9532);
+});
+
+test('ReverseInt flips a negative number', () => {
+    expect(reverseInt(-5)).toEqual(-5);
+    expect(reverseInt(-15)).toEqual(-51);
+    expect(reverseInt(-90)).toEqual(-9);
+    expect(reverseInt(-2359)).toEqual(-9532);
+});