From 4280c6240b88dadc8e5ea187b78c10aca9dfc163 Mon Sep 17 00:00:00 2001
From: "(quasar) nebula" <qznebula@protonmail.com>
Date: Tue, 2 May 2023 14:58:27 -0300
Subject: contracts: initial commit

All draft stuff here for now, but this is *relatively* un-naive
as it's based on a lot of recent research and discussion.
But none of this code is evaluated yet!!
---
 src/content/contracts/adjacentAlbumsInGroup.js | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 src/content/contracts/adjacentAlbumsInGroup.js

(limited to 'src/content/contracts')

diff --git a/src/content/contracts/adjacentAlbumsInGroup.js b/src/content/contracts/adjacentAlbumsInGroup.js
new file mode 100644
index 00000000..e982fa5b
--- /dev/null
+++ b/src/content/contracts/adjacentAlbumsInGroup.js
@@ -0,0 +1,17 @@
+export default {
+  hook(contract, [album, group]) {
+    contract.provide({
+      group,
+      album,
+      albums: contract.selectProperty(group, 'albums'),
+    });
+  },
+
+  compute({group, album, albums}) {
+    const datedAlbums = albums.filter(album => album.date);
+    const index = datedAlbums.indexOf(album);
+    const previousAlbum = (index > 0) && datedAlbums[index - 1];
+    const nextAlbum = (index < datedAlbums.length - 1) && datedAlbums[index + 1];
+    return {previousAlbum, nextAlbum};
+  },
+};
-- 
cgit 1.3.0-6-gf8a5