1 files changed, 87 insertions, 0 deletions
diff --git a/src/content/dependencies/listTracksByDurationInAlbum.js b/src/content/dependencies/listTracksByDurationInAlbum.js
new file mode 100644
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+++ b/src/content/dependencies/listTracksByDurationInAlbum.js
@@ -0,0 +1,87 @@
+import {sortByCount, sortChronologically} from '#sort';
+import {filterByCount, filterMultipleArrays, stitchArrays} from '#sugar';
+
+export default {
+  contentDependencies: ['generateListingPage', 'linkAlbum', 'linkTrack'],
+  extraDependencies: ['language', 'wikiData'],
+
+  sprawl({albumData}) {
+    return {albumData};
+  },
+
+  query({albumData}, spec) {
+    const albums = sortChronologically(albumData.slice());
+
+    const tracks =
+      albums.map(album =>
+        album.tracks.slice());
+
+    const durations =
+      tracks.map(tracks =>
+        tracks.map(track =>
+          track.duration));
+
+    // Filter out tracks without any duration.
+    // Sort at the same time, to avoid redundantly stitching again later.
+    const stitched = stitchArrays({tracks, durations});
+    for (const {tracks, durations} of stitched) {
+      filterByCount(tracks, durations);
+      sortByCount(tracks, durations, {greatestFirst: true});
+    }
+
+    // Filter out albums which don't have at least two (remaining) tracks.
+    // If the album only has one track in the first place, or if only one
+    // has any duration, then there aren't any comparisons to be made and
+    // it just takes up space on the listing page.
+    const numTracks = tracks.map(tracks => tracks.length);
+    filterMultipleArrays(albums, tracks, durations, numTracks,
+      (album, tracks, durations, numTracks) =>
+        numTracks >= 2);
+
+    return {spec, albums, tracks, durations};
+  },
+
+  relations(relation, query) {
+    return {
+      page: relation('generateListingPage', query.spec),
+
+      albumLinks:
+        query.albums
+          .map(album => relation('linkAlbum', album)),
+
+      trackLinks:
+        query.tracks
+          .map(tracks => tracks
+            .map(track => relation('linkTrack', track))),
+    };
+  },
+
+  data(query) {
+    return {
+      durations: query.durations,
+    };
+  },
+
+  generate(data, relations, {language}) {
+    return relations.page.slots({
+      type: 'chunks',
+
+      chunkTitles:
+        relations.albumLinks
+          .map(albumLink => ({album: albumLink})),
+
+      chunkRows:
+        stitchArrays({
+          trackLinks: relations.trackLinks,
+          durations: data.durations,
+        }).map(({trackLinks, durations}) =>
+            stitchArrays({
+              trackLink: trackLinks,
+              duration: durations,
+            }).map(({trackLink, duration}) => ({
+                track: trackLink,
+                duration: language.formatDuration(duration),
+              }))),
+    });
+  },
+};