feat: add weight conversion kilograms to pounds and vice versa

Conversions/WeightConversion.js

@@ -0,0 +1,33 @@
+/**
+ * @function kilogramsToPounds
+ * @description Converts weight from kilograms to pounds.
+ * @param {number} kg - Weight in kilograms
+ * @returns {number} - Weight in pounds
+ * @see https://en.wikipedia.org/wiki/Pound_(mass)
+ * @example kilogramsToPounds(1) => 2.20462
+ * @example kilogramsToPounds(10) => 22.0462
+ */
+const kilogramsToPounds = (kg) => {
+  if (typeof kg !== 'number' || isNaN(kg)) {
+    throw new TypeError('Input must be a number')
+  }
+  return kg * 2.20462
+}
+
+/**
+ * @function poundsToKilograms
+ * @description Converts weight from pounds to kilograms.
+ * @param {number} pounds - Weight in pounds
+ * @returns {number} - Weight in kilograms
+ * @see https://en.wikipedia.org/wiki/Kilogram
+ * @example poundsToKilograms(1) => 0.453592
+ * @example poundsToKilograms(10) => 4.53592
+ */
+const poundsToKilograms = (pounds) => {
+  if (typeof pounds !== 'number' || isNaN(pounds)) {
+    throw new TypeError('Input must be a number')
+  }
+  return pounds * 0.453592
+}
+
+export { kilogramsToPounds, poundsToKilograms }

Conversions/test/WeightConversion.test.js

@@ -0,0 +1,53 @@
+import { kilogramsToPounds, poundsToKilograms } from '../WeightConversion.js'
+
+describe('kilogramsToPounds', () => {
+  test('kilogramsToPounds(0) returns 0', () => {
+    expect(kilogramsToPounds(0)).toBe(0)
+  })
+
+  test('kilogramsToPounds(1) returns 2.20462', () => {
+    expect(kilogramsToPounds(1)).toBeCloseTo(2.20462)
+  })
+
+  test('kilogramsToPounds(10) returns 22.0462', () => {
+    expect(kilogramsToPounds(10)).toBeCloseTo(22.0462)
+  })
+
+  test('kilogramsToPounds(70) returns 154.324', () => {
+    expect(kilogramsToPounds(70)).toBeCloseTo(154.324)
+  })
+
+  test('throws TypeError for non-number input', () => {
+    expect(() => kilogramsToPounds('10')).toThrow(TypeError)
+  })
+
+  test('throws TypeError for NaN', () => {
+    expect(() => kilogramsToPounds(NaN)).toThrow(TypeError)
+  })
+})
+
+describe('poundsToKilograms', () => {
+  test('poundsToKilograms(0) returns 0', () => {
+    expect(poundsToKilograms(0)).toBe(0)
+  })
+
+  test('poundsToKilograms(1) returns 0.453592', () => {
+    expect(poundsToKilograms(1)).toBeCloseTo(0.453592)
+  })
+
+  test('poundsToKilograms(10) returns 4.53592', () => {
+    expect(poundsToKilograms(10)).toBeCloseTo(4.53592)
+  })
+
+  test('poundsToKilograms(150) returns 68.0388', () => {
+    expect(poundsToKilograms(150)).toBeCloseTo(68.0388)
+  })
+
+  test('throws TypeError for non-number input', () => {
+    expect(() => poundsToKilograms('10')).toThrow(TypeError)
+  })
+
+  test('throws TypeError for NaN', () => {
+    expect(() => poundsToKilograms(NaN)).toThrow(TypeError)
+  })
+})