feat(reverse): introduce reverse

reverse.ts

@@ -0,0 +1,24 @@
+/**
+  * Returns the elements of an iterable in reverse order.
+  *
+  * @param iterable The iterable to reverse.
+  * @returns The elements of the iterable in reverse order.
+  *
+  * @example
+  * ```ts
+  * import { reverse } from "@core/iterutil/reverse";
+  *
+  * console.log([...reverse([1, 2, 3)]); // [3, 2, 1]
+  * console.log([...reverse([])]); // []
+  * ```
+  */
+export function reverse<T>(iterable: Iterable<T>): Iterable<T> {
+  return {
+    *[Symbol.iterator]() {
+      const array = [...iterable];
+      for (let i = array.length - 1; i >= 0; i--) {
+        yield array[i];
+      }
+    },
+  };
+}

reverse_test.ts

@@ -0,0 +1,18 @@
+import { test } from "@cross/test";
+import { assertEquals } from "@std/assert";
+import { assertType, type IsExact } from "@std/testing/types";
+import { reverse } from "./reverse.ts";
+
+await test("reverse with non empty iterable", () => {
+  const result = reverse([1, 2, 3, 4, 5] as const);
+  const expected = [5, 4, 3, 2, 1] as const;
+  assertEquals(result, expected);
+  assertType<IsExact<typeof result, Iterable<[5, 4, 3, 2, 1]>>>(true);
+});
+
+await test("reverse with empty iterable", () => {
+  const result = reverse([] as number[]);
+  const expected = [];
+  assertEquals(result, expected);
+  assertType<IsExact<typeof result, number[]>>(true);
+});