feat: integer reversal algorithm

Author: francislagares

src/algorithms/integer-reverse/integer-reversal.ts

@@ -0,0 +1,9 @@
+export const reverseInt = (int: number) => {
+  const reversed = int.toString().split('').reverse().join('');
+
+  if (int < 0) {
+    return parseInt(reversed) * Math.sign(int);
+  }
+
+  return parseInt(reversed);
+};

src/algorithms/integer-reverse/tests/integer-reverse.test.ts

@@ -0,0 +1,27 @@
+import { describe, test } from 'vitest';
+
+import { reverseInt } from '../integer-reversal';
+
+describe('Integer Reversal', () => {
+  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);
+  });
+});