feat: add array compact algorithm

Data-Structures/Array/Compact.js

@@ -0,0 +1,18 @@
+/**
+ * @function compact
+ * @description Removes all falsy values from an array.
+ *   Falsy values are: false, null, 0, "", undefined, NaN.
+ * @param {Array} arr - The input array
+ * @returns {Array} - A new array with all falsy values removed
+ * @see https://en.wikipedia.org/wiki/Truthiness
+ * @example compact([1, false, 2, null, 3, undefined]) => [1, 2, 3]
+ * @example compact([0, 1, "", 2, NaN, 3]) => [1, 2, 3]
+ */
+const compact = (arr) => {
+  if (!Array.isArray(arr)) {
+    throw new TypeError('Input must be an array')
+  }
+  return arr.filter(Boolean)
+}
+
+export { compact }

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

@@ -0,0 +1,53 @@
+import { compact } from '../Compact.js'
+
+describe('compact', () => {
+  test('compact removes false values', () => {
+    expect(compact([1, false, 2])).toEqual([1, 2])
+  })
+
+  test('compact removes null values', () => {
+    expect(compact([1, null, 2])).toEqual([1, 2])
+  })
+
+  test('compact removes undefined values', () => {
+    expect(compact([1, undefined, 2])).toEqual([1, 2])
+  })
+
+  test('compact removes 0 values', () => {
+    expect(compact([1, 0, 2])).toEqual([1, 2])
+  })
+
+  test('compact removes empty string values', () => {
+    expect(compact([1, '', 2])).toEqual([1, 2])
+  })
+
+  test('compact removes NaN values', () => {
+    expect(compact([1, NaN, 2])).toEqual([1, 2])
+  })
+
+  test('compact removes all falsy values together', () => {
+    expect(compact([1, false, 2, null, 3, undefined])).toEqual([1, 2, 3])
+  })
+
+  test('compact empty array returns empty array', () => {
+    expect(compact([])).toEqual([])
+  })
+
+  test('compact array with no falsy values returns same values', () => {
+    expect(compact([1, 2, 3])).toEqual([1, 2, 3])
+  })
+
+  test('compact does not mutate original array', () => {
+    const arr = [1, false, 2, null]
+    compact(arr)
+    expect(arr).toEqual([1, false, 2, null])
+  })
+
+  test('throws TypeError for non-array input', () => {
+    expect(() => compact('123')).toThrow(TypeError)
+  })
+
+  test('throws TypeError for null input', () => {
+    expect(() => compact(null)).toThrow(TypeError)
+  })
+})