From 1f212c00e1c5d23b4c733564aacfb0ccf127c412 Mon Sep 17 00:00:00 2001
From: Iku-turso <mikko.aspiala@gmail.com>
Date: Sun, 15 Jan 2023 13:30:45 +0200
Subject: [PATCH] feat: Introduce movingWindow in fp

---
 packages/fp/src/movingWindow/movingWindow.js      |  8 ++++++++
 packages/fp/src/movingWindow/movingWindow.test.js | 13 +++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 packages/fp/src/movingWindow/movingWindow.js
 create mode 100644 packages/fp/src/movingWindow/movingWindow.test.js

diff --git a/packages/fp/src/movingWindow/movingWindow.js b/packages/fp/src/movingWindow/movingWindow.js
new file mode 100644
index 00000000..3b974d00
--- /dev/null
+++ b/packages/fp/src/movingWindow/movingWindow.js
@@ -0,0 +1,8 @@
+export default windowSize => things =>
+  things.reduce(
+    (accumulated, currentThing, index, allThings) =>
+      index > allThings.length - windowSize
+        ? accumulated
+        : [...accumulated, allThings.slice(index, index + windowSize)],
+    [],
+  );
diff --git a/packages/fp/src/movingWindow/movingWindow.test.js b/packages/fp/src/movingWindow/movingWindow.test.js
new file mode 100644
index 00000000..61d8f305
--- /dev/null
+++ b/packages/fp/src/movingWindow/movingWindow.test.js
@@ -0,0 +1,13 @@
+import movingWindow from './movingWindow';
+
+describe('movingWindow', () => {
+  it('iterates an n-width window through an array', () => {
+    const actual = movingWindow(3)([1, 2, 3, 4, 5]);
+
+    expect(actual).toEqual([
+      [1, 2, 3],
+      [2, 3, 4],
+      [3, 4, 5],
+    ]);
+  });
+});