feat: add array findMax and findMin algorithms

Data-Structures/Array/MaxMin.js

@@ -0,0 +1,39 @@
+/**
+ * @function findMax
+ * @description Finds the maximum value in an array of numbers
+ *   without using JavaScript's built-in Math.max().
+ * @param {number[]} arr - An array of numbers
+ * @returns {number} - The maximum value
+ * @see https://en.wikipedia.org/wiki/Maximum_and_minimum
+ * @example findMax([1, 5, 3, 9, 2]) => 9
+ */
+const findMax = (arr) => {
+  if (!Array.isArray(arr) || arr.length === 0) {
+    throw new TypeError('Input must be a non-empty array')
+  }
+  if (!arr.every((n) => typeof n === 'number' && !isNaN(n))) {
+    throw new TypeError('All elements must be numbers')
+  }
+  return arr.reduce((max, n) => (n > max ? n : max), arr[0])
+}
+
+/**
+ * @function findMin
+ * @description Finds the minimum value in an array of numbers
+ *   without using JavaScript's built-in Math.min().
+ * @param {number[]} arr - An array of numbers
+ * @returns {number} - The minimum value
+ * @see https://en.wikipedia.org/wiki/Maximum_and_minimum
+ * @example findMin([1, 5, 3, 9, 2]) => 1
+ */
+const findMin = (arr) => {
+  if (!Array.isArray(arr) || arr.length === 0) {
+    throw new TypeError('Input must be a non-empty array')
+  }
+  if (!arr.every((n) => typeof n === 'number' && !isNaN(n))) {
+    throw new TypeError('All elements must be numbers')
+  }
+  return arr.reduce((min, n) => (n < min ? n : min), arr[0])
+}
+
+export { findMax, findMin }

Data-Structures/Array/test/MaxMin.test.js

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+import { findMax, findMin } from '../MaxMin.js'
+
+describe('findMax', () => {
+  test('findMax([1,5,3,9,2]) returns 9', () => {
+    expect(findMax([1, 5, 3, 9, 2])).toBe(9)
+  })
+
+  test('findMax single element returns that element', () => {
+    expect(findMax([5])).toBe(5)
+  })
+
+  test('findMax with negative numbers', () => {
+    expect(findMax([-3, -1, -5])).toBe(-1)
+  })
+
+  test('findMax with all same values', () => {
+    expect(findMax([3, 3, 3])).toBe(3)
+  })
+
+  test('throws TypeError for empty array', () => {
+    expect(() => findMax([])).toThrow(TypeError)
+  })
+
+  test('throws TypeError for non-array input', () => {
+    expect(() => findMax('123')).toThrow(TypeError)
+  })
+})
+
+describe('findMin', () => {
+  test('findMin([1,5,3,9,2]) returns 1', () => {
+    expect(findMin([1, 5, 3, 9, 2])).toBe(1)
+  })
+
+  test('findMin single element returns that element', () => {
+    expect(findMin([5])).toBe(5)
+  })
+
+  test('findMin with negative numbers', () => {
+    expect(findMin([-3, -1, -5])).toBe(-5)
+  })
+
+  test('findMin with all same values', () => {
+    expect(findMin([3, 3, 3])).toBe(3)
+  })
+
+  test('throws TypeError for empty array', () => {
+    expect(() => findMin([])).toThrow(TypeError)
+  })
+
+  test('throws TypeError for non-array input', () => {
+    expect(() => findMin('123')).toThrow(TypeError)
+  })
+})