3 files changed, 76 insertions, 12 deletions

diff --git a/src/data/composite/things/album/index.js b/src/data/composite/things/album/index.js
index 8b5098f0..dfc6864f 100644
--- a/src/data/composite/things/album/index.js
+++ b/src/data/composite/things/album/index.js
@@ -1 +1,2 @@
+export {default as withHasCoverArt} from './withHasCoverArt.js';
 export {default as withTracks} from './withTracks.js';
diff --git a/src/data/composite/things/album/withHasCoverArt.js b/src/data/composite/things/album/withHasCoverArt.js
new file mode 100644
index 00000000..fd3f2894
--- /dev/null
+++ b/src/data/composite/things/album/withHasCoverArt.js
@@ -0,0 +1,64 @@
+// TODO: This shouldn't be coded as an Album-specific thing,
+// or even really to do with cover artworks in particular, either.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency, withResultOfAvailabilityCheck}
+  from '#composite/control-flow';
+import {fillMissingListItems, withFlattenedList, withPropertyFromList}
+  from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: 'withHasCoverArt',
+
+  outputs: ['#hasCoverArt'],
+
+  steps: () => [
+    withResultOfAvailabilityCheck({
+      from: 'coverArtistContribs',
+      mode: input.value('empty'),
+    }),
+
+    {
+      dependencies: ['#availability'],
+      compute: (continuation, {
+        ['#availability']: availability,
+      }) =>
+        (availability
+          ? continuation.raiseOutput({
+              ['#hasCoverArt']: true,
+            })
+          : continuation()),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: 'coverArtworks',
+      mode: input.value('empty'),
+      output: input.value({'#hasCoverArt': false}),
+    }),
+
+    withPropertyFromList({
+      list: 'coverArtworks',
+      property: input.value('artistContribs'),
+      internal: input.value(true),
+    }),
+
+    // Since we're getting the update value for each artwork's artistContribs,
+    // it may not be set at all, and in that case won't be exposing as [].
+    fillMissingListItems({
+      list: '#coverArtworks.artistContribs',
+      fill: input.value([]),
+    }),
+
+    withFlattenedList({
+      list: '#coverArtworks.artistContribs',
+    }),
+
+    withResultOfAvailabilityCheck({
+      from: '#flattenedList',
+      mode: input.value('empty'),
+    }).outputs({
+      '#availability': '#hasCoverArt',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/track/withHasUniqueCoverArt.js b/src/data/composite/things/track/withHasUniqueCoverArt.js
index af68073e..85d3b92a 100644
--- a/src/data/composite/things/track/withHasUniqueCoverArt.js
+++ b/src/data/composite/things/track/withHasUniqueCoverArt.js
@@ -15,7 +15,8 @@ import {input, templateCompositeFrom} from '#composite';
 
 import {raiseOutputWithoutDependency, withResultOfAvailabilityCheck}
   from '#composite/control-flow';
-import {withFlattenedList, withPropertyFromList} from '#composite/data';
+import {fillMissingListItems, withFlattenedList, withPropertyFromList}
+  from '#composite/data';
 
 import withPropertyFromAlbum from './withPropertyFromAlbum.js';
 
@@ -86,6 +87,13 @@ export default templateCompositeFrom({
       internal: input.value(true),
     }),
 
+    // Since we're getting the update value for each artwork's artistContribs,
+    // it may not be set at all, and in that case won't be exposing as [].
+    fillMissingListItems({
+      list: '#trackArtworks.artistContribs',
+      fill: input.value([]),
+    }),
+
     withFlattenedList({
       list: '#trackArtworks.artistContribs',
     }),
@@ -93,17 +101,8 @@ export default templateCompositeFrom({
     withResultOfAvailabilityCheck({
       from: '#flattenedList',
       mode: input.value('empty'),
+    }).outputs({
+      '#availability': '#hasUniqueCoverArt',
     }),
-
-    {
-      dependencies: ['#availability'],
-      compute: (continuation, {
-        ['#availability']: availability,
-      }) =>
-        continuation({
-          ['#hasUniqueCoverArt']:
-            availability,
-        }),
-    },
   ],
 });