From 2f2964662221b2c632e1f7036ec6492ae55e5b66 Mon Sep 17 00:00:00 2001
From: Daniel Cassidy <mail@danielcassidy.me.uk>
Date: Sat, 15 Jan 2022 13:18:06 +0000
Subject: [PATCH] fix(reverse): reverse should not modify original array

---
 index.test.ts | 7 +++++++
 index.ts      | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/index.test.ts b/index.test.ts
index 0ff41bb8..6d2da170 100644
--- a/index.test.ts
+++ b/index.test.ts
@@ -43,6 +43,7 @@ import {
     product,
     remove,
     removeFirst,
+    reverse,
     scan,
     scan1,
     scanRight,
@@ -100,6 +101,12 @@ test("empty", t => {
     t.false(empty([1, 2, 3]));
 });
 
+test("reverse", t => {
+    const a = [1, 2, 4, 3];
+    t.deepEqual(reverse(a), [3, 4, 2, 1]);
+    t.deepEqual(a, [1, 2, 4, 3]); // Ensure original array is untouched.
+});
+
 test("slice", t => {
     t.deepEqual(slice([1, 2, 3, 4], 1), [2, 3, 4]);
     t.deepEqual(slice([1, 2, 3, 4, 5], 1, 4), [2, 3, 4]);
diff --git a/index.ts b/index.ts
index 3a892f03..b1967501 100644
--- a/index.ts
+++ b/index.ts
@@ -113,7 +113,7 @@ export function notEmpty<T>(array: ArrayLike<T>): boolean {
 }
 
 export function reverse<T>(array: ArrayLike<T>): T[] {
-    return nativeReverse.call(array);
+    return nativeReverse.call(copy(array));
 }
 
 export function slice<T>(array: ArrayLike<T>, start?: number, end?: number): T[] {