feat(compat): implement unzip (#770)

* feat(compat): implement unzip

* jsdoc

* make lint happy

---------

Co-authored-by: Sojin Park <[email protected]>

benchmarks/performance/unzip.bench.ts

@@ -1,8 +1,10 @@
 import { bench, describe } from 'vitest';
 import { unzip as unzipToolkit_ } from 'es-toolkit';
+import { unzip as unzipToolkitCompat_ } from 'es-toolkit/compat';
 import { unzip as unzipLodash_ } from 'lodash';
 
 const unzipToolkit = unzipToolkit_;
+const unzipToolkitCompat = unzipToolkitCompat_;
 const unzipLodash = unzipLodash_;
 
 describe('unzip, small arrays', () => {
@@ -13,6 +15,13 @@ describe('unzip, small arrays', () => {
     ]);
   });
 
+  bench('es-toolkit/compat/unzip', () => {
+    unzipToolkitCompat([
+      ['a', 1, true],
+      ['b', 2, false],
+    ]);
+  });
+
   bench('lodash/unzip', () => {
     unzipLodash([
       ['a', 1, true],
@@ -28,6 +37,10 @@ describe('unzip, large arrays', () => {
     unzipToolkit(largeArray);
   });
 
+  bench('es-toolkit/compat/unzip', () => {
+    unzipToolkitCompat(largeArray);
+  });
+
   bench('lodash/unzip', () => {
     unzipLodash(largeArray);
   });

src/compat/array/unzip.spec.ts

@@ -0,0 +1,75 @@
+import { describe, expect, it } from 'vitest';
+import { unzip } from './unzip';
+import { zip } from '../../array/zip';
+
+describe('unzip', () => {
+  const object = {
+    'an empty array': [[], []],
+    '2-tuples': [
+      [
+        ['barney', 'fred'],
+        [36, 40],
+      ],
+      [
+        ['barney', 36],
+        ['fred', 40],
+      ],
+    ],
+    '3-tuples': [
+      [
+        ['barney', 'fred'],
+        [36, 40],
+        [false, true],
+      ],
+      [
+        ['barney', 36, false],
+        ['fred', 40, true],
+      ],
+    ],
+  };
+
+  Object.entries(object).forEach(([key, pair]) => {
+    it(`\`_.unzip\` should work with ${key}`, () => {
+      const actual = unzip(pair[1]);
+      expect(actual).toEqual(pair[0]);
+    });
+  });
+
+  it(`\`_.unzip\` should work with tuples of different lengths`, () => {
+    const pair = [
+      [
+        ['barney', 36],
+        ['fred', 40, false],
+      ],
+      [
+        ['barney', 'fred'],
+        [36, 40],
+        [undefined, false],
+      ],
+    ];
+    const actual = unzip(pair[1]) as any;
+    expect('2' in actual[0]).toBeTruthy();
+    expect(actual).toEqual([
+      ['barney', 36, undefined],
+      ['fred', 40, false],
+    ]);
+  });
+
+  it(`\`_.unzip\` should support consuming its return value`, () => {
+    const expected = [
+      ['barney', 'fred'],
+      [36, 40],
+    ];
+    // @ts-expect-error - TS doesn't support array types in rest parameters
+    expect(unzip(zip(...unzip(zip(...expected))))).toEqual(expected);
+  });
+
+  it(`\`_.unzip\` should work with array-like object`, () => {
+    const array = { 0: { 0: 'a', 1: 1, length: 2 }, 1: { 0: 'b', 1: 2, length: 2 }, length: 2 };
+    const actual = unzip(array);
+    expect(actual).toEqual([
+      ['a', 'b'],
+      [1, 2],
+    ]);
+  });
+});

src/compat/array/unzip.ts

@@ -0,0 +1,25 @@
+import { unzip as unzipToolkit } from '../../array/unzip.ts';
+import { isArrayLikeObject } from '../predicate/isArrayLikeObject.ts';
+
+/**
+ * Gathers elements in the same position in an internal array
+ * from a grouped array of elements and returns them as a new array.
+ *
+ * @template T - The type of elements in the nested array.
+ * @param {T[][] | ArrayLike<ArrayLike<T>> | null | undefined} array - The nested array to unzip.
+ * @returns {T[][]} A new array of unzipped elements.
+ *
+ * @example
+ * const zipped = [['a', true, 1],['b', false, 2]];
+ * const result = unzip(zipped);
+ * // result will be [['a', 'b'], [true, false], [1, 2]]
+ */
+export function unzip<T>(array: T[][] | ArrayLike<ArrayLike<T>> | null | undefined): T[][] {
+  if (!isArrayLikeObject(array) || !array.length) {
+    return [];
+  }
+  if (Array.isArray(array)) {
+    return unzipToolkit(array);
+  }
+  return unzipToolkit(Array.from(array, value => Array.from(value)));
+}

src/compat/index.ts

@@ -61,6 +61,7 @@ export { tail } from './array/tail.ts';
 export { take } from './array/take.ts';
 export { takeRight } from './array/takeRight.ts';
 export { uniq } from './array/uniq.ts';
+export { unzip } from './array/unzip.ts';
 export { without } from './array/without.ts';
 export { zipObjectDeep } from './array/zipObjectDeep.ts';