3 files changed, 91 insertions, 0 deletions
diff --git a/src/data/composite/things/track-section/index.js b/src/data/composite/things/track-section/index.js
index 3202ed49..f11a2ab5 100644
--- a/src/data/composite/things/track-section/index.js
+++ b/src/data/composite/things/track-section/index.js
@@ -1 +1,3 @@
 export {default as withAlbum} from './withAlbum.js';
+export {default as withContinueCountingFrom} from './withContinueCountingFrom.js';
+export {default as withStartCountingFrom} from './withStartCountingFrom.js';
diff --git a/src/data/composite/things/track-section/withContinueCountingFrom.js b/src/data/composite/things/track-section/withContinueCountingFrom.js
new file mode 100644
index 00000000..e034b7a5
--- /dev/null
+++ b/src/data/composite/things/track-section/withContinueCountingFrom.js
@@ -0,0 +1,25 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import withStartCountingFrom from './withStartCountingFrom.js';
+
+export default templateCompositeFrom({
+  annotation: `withContinueCountingFrom`,
+
+  outputs: ['#continueCountingFrom'],
+
+  steps: () => [
+    withStartCountingFrom(),
+
+    {
+      dependencies: ['#startCountingFrom', 'tracks'],
+      compute: (continuation, {
+        ['#startCountingFrom']: startCountingFrom,
+        ['tracks']: tracks,
+      }) => continuation({
+        ['#continueCountingFrom']:
+          startCountingFrom +
+          tracks.length,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/track-section/withStartCountingFrom.js b/src/data/composite/things/track-section/withStartCountingFrom.js
new file mode 100644
index 00000000..ef345327
--- /dev/null
+++ b/src/data/composite/things/track-section/withStartCountingFrom.js
@@ -0,0 +1,64 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withNearbyItemFromList, withPropertyFromObject} from '#composite/data';
+
+import withAlbum from './withAlbum.js';
+
+export default templateCompositeFrom({
+  annotation: `withStartCountingFrom`,
+
+  inputs: {
+    from: input({
+      type: 'number',
+      defaultDependency: 'startCountingFrom',
+      acceptsNull: true,
+    }),
+  },
+
+  outputs: ['#startCountingFrom'],
+
+  steps: () => [
+    {
+      dependencies: [input('from')],
+      compute: (continuation, {
+        [input('from')]: from,
+      }) =>
+        (from === null
+          ? continuation()
+          : continuation.raiseOutput({'#startCountingFrom': from})),
+    },
+
+    withAlbum(),
+
+    raiseOutputWithoutDependency({
+      dependency: '#album',
+      output: input.value({'#startCountingFrom': 1}),
+    }),
+
+    withPropertyFromObject({
+      object: '#album',
+      property: input.value('trackSections'),
+    }),
+
+    withNearbyItemFromList({
+      list: '#album.trackSections',
+      item: input.myself(),
+      offset: input.value(-1),
+    }).outputs({
+      '#nearbyItem': '#previousTrackSection',
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#previousTrackSection',
+      output: input.value({'#startCountingFrom': 1}),
+    }),
+
+    withPropertyFromObject({
+      object: '#previousTrackSection',
+      property: input.value('continueCountingFrom'),
+    }).outputs({
+      '#previousTrackSection.continueCountingFrom': '#startCountingFrom',
+    }),
+  ],
+});