feat: add power (exponentiation by squaring) algorithm

Maths/Power.js

@@ -0,0 +1,29 @@
+/**
+ * @function power
+ * @description Calculates base raised to the power of exponent
+ *   without using JavaScript's built-in Math.pow() or ** operator.
+ *   Uses fast exponentiation (exponentiation by squaring).
+ * @param {number} base - The base number
+ * @param {number} exponent - A non-negative integer exponent
+ * @returns {number} - base raised to the power of exponent
+ * @see https://en.wikipedia.org/wiki/Exponentiation_by_squaring
+ * @example power(2, 10) => 1024
+ * @example power(3, 4) => 81
+ * @example power(5, 0) => 1
+ */
+const power = (base, exponent) => {
+  if (typeof base !== 'number' || isNaN(base)) {
+    throw new TypeError('Base must be a number')
+  }
+  if (!Number.isInteger(exponent) || exponent < 0) {
+    throw new TypeError('Exponent must be a non-negative integer')
+  }
+  if (exponent === 0) return 1
+  if (exponent % 2 === 0) {
+    const half = power(base, exponent / 2)
+    return half * half
+  }
+  return base * power(base, exponent - 1)
+}
+
+export { power }

Maths/test/Power.test.js

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+import { power } from '../Power.js'
+
+describe('power', () => {
+  test('power(2, 0) returns 1', () => {
+    expect(power(2, 0)).toBe(1)
+  })
+
+  test('power(2, 1) returns 2', () => {
+    expect(power(2, 1)).toBe(2)
+  })
+
+  test('power(2, 10) returns 1024', () => {
+    expect(power(2, 10)).toBe(1024)
+  })
+
+  test('power(3, 4) returns 81', () => {
+    expect(power(3, 4)).toBe(81)
+  })
+
+  test('power(5, 0) returns 1', () => {
+    expect(power(5, 0)).toBe(1)
+  })
+
+  test('power(10, 3) returns 1000', () => {
+    expect(power(10, 3)).toBe(1000)
+  })
+
+  test('power(0, 5) returns 0', () => {
+    expect(power(0, 5)).toBe(0)
+  })
+
+  test('power(1, 100) returns 1', () => {
+    expect(power(1, 100)).toBe(1)
+  })
+
+  test('power with negative base', () => {
+    expect(power(-2, 3)).toBe(-8)
+  })
+
+  test('throws TypeError for non-number base', () => {
+    expect(() => power('2', 3)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for negative exponent', () => {
+    expect(() => power(2, -1)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for float exponent', () => {
+    expect(() => power(2, 1.5)).toThrow(TypeError)
+  })
+})