fix(reverse): reverse should not modify original array

softwareventures · Jan 15, 2022 · 92eff1d · 92eff1d
1 parent 9052e1e
commit 92eff1d
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/index.test.ts b/index.test.ts
@@ -41,6 +41,7 @@ import {
     product,
     remove,
     removeFirst,
+    reverse,
     scan,
     scan1,
     scanRight,
@@ -90,6 +91,12 @@ 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
@@ -107,7 +107,7 @@ 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[] {