Adding new modules and test files.

Author: ThatGuyNick05

src/arrayUtils.ts

@@ -0,0 +1,8 @@
+export function findMax(numbers: number[]): number | null {
+  if (numbers.length === 0) return null;
+  return Math.max(...numbers);
+}
+
+export function deduplicate<T>(arr: T[]): T[] {
+  return [...new Set(arr)];
+}

src/math.ts

@@ -0,0 +1,7 @@
+export function multiply(a: number, b: number): number {
+  return a * b;
+}
+
+export function isEven(n: number): boolean {
+  return n % 2 === 0;
+}

src/stringUtils.ts

@@ -0,0 +1,8 @@
+export function reverseString(str: string): string {
+  return str.split('').reverse().join('');
+}
+
+export function capitalizeFirst(str: string): string {
+  if (!str) return '';
+  return str[0].toUpperCase() + str.slice(1);
+}

tests/arrayUtils.ts

@@ -0,0 +1,12 @@
+import { findMax, deduplicate } from '../src/arrayUtils';
+
+describe('arrayUtils.ts', () => {
+  test('finds max in array', () => {
+    expect(findMax([1, 2, 3, 9, 5])).toBe(9);
+    expect(findMax([])).toBeNull();
+  });
+
+  test('removes duplicate values from array', () => {
+    expect(deduplicate([1, 2, 2, 3, 3, 3])).toEqual([1, 2, 3]);
+  });
+});

tests/index.test.ts

@@ -1,5 +1,11 @@
 import { add } from '../src/index';
 
-test('adds 2 + 2 to equal 4', () => {
-  expect(add(2, 2)).toBe(4);
+describe('index.ts', () => {
+  test('adds positive numbers correctly', () => {
+    expect(add(3, 7)).toBe(10);
+  });
+
+  test('adds negative numbers correctly', () => {
+    expect(add(-5, -6)).toBe(-11);
+  });
 });

tests/math.test.ts

@@ -0,0 +1,12 @@
+import { multiply, isEven } from '../src/math';
+
+describe('math.ts', () => {
+  test('multiplies numbers correctly', () => {
+    expect(multiply(4, 5)).toBe(20);
+  });
+
+  test('detects even numbers', () => {
+    expect(isEven(4)).toBe(true);
+    expect(isEven(5)).toBe(false);
+  });
+});

tests/stringUtils.test.ts

@@ -0,0 +1,12 @@
+import { reverseString, capitalizeFirst } from '../src/stringUtils';
+
+describe('stringUtils.ts', () => {
+  test('reverses a string', () => {
+    expect(reverseString('hello')).toBe('olleh');
+  });
+
+  test('capitalizes first letter', () => {
+    expect(capitalizeFirst('world')).toBe('World');
+    expect(capitalizeFirst('')).toBe('');
+  });
+});