From a07625032fc22e9a331c110dc52137d7aa488019 Mon Sep 17 00:00:00 2001
From: Markus Sanin <markus.sanin@zeppelin-group.com>
Date: Wed, 31 Jul 2024 12:45:48 +0200
Subject: [PATCH 1/2] Fix error `TypeError: items[0] is undefined`

---
 addon/src/modifiers/sortable-item.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/addon/src/modifiers/sortable-item.js b/addon/src/modifiers/sortable-item.js
index 1c767bc6..cf8215b5 100644
--- a/addon/src/modifiers/sortable-item.js
+++ b/addon/src/modifiers/sortable-item.js
@@ -826,7 +826,7 @@ export default class SortableItemModifier extends Modifier {
    */
   get transitionDuration() {
     const items = this.sortableGroup.sortedItems.filter((x) => !x.isDragging && !x.isDropping);
-    let el = items[0].element ?? this.element; // Fallback when only one element is present in list
+    let el = items[0]?.element ?? this.element; // Fallback when only one element is present in list
     let rule = getComputedStyle(el).transitionDuration;
     let match = rule.match(/([\d.]+)([ms]*)/);
 

From 5d5826874765ed3b3e1413596a051642e36ba557 Mon Sep 17 00:00:00 2001
From: Markus Sanin <markus.sanin@zeppelin-group.com>
Date: Sat, 3 Aug 2024 10:44:41 +0200
Subject: [PATCH 2/2] Add test for `transitionDuration` when only one item is
 present which will be moved

---
 .../modifiers/sortable-item-test.js           | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 test-app/tests/integration/modifiers/sortable-item-test.js

diff --git a/test-app/tests/integration/modifiers/sortable-item-test.js b/test-app/tests/integration/modifiers/sortable-item-test.js
new file mode 100644
index 00000000..0d54f003
--- /dev/null
+++ b/test-app/tests/integration/modifiers/sortable-item-test.js
@@ -0,0 +1,36 @@
+import { module, test } from 'qunit';
+import { setupRenderingTest } from 'ember-qunit';
+import { find, render } from '@ember/test-helpers';
+import { set } from '@ember/object';
+import { drag } from 'ember-sortable/test-support';
+import hbs from 'htmlbars-inline-precompile';
+
+module('Integration | Modifier | sortable-item', function (hooks) {
+  setupRenderingTest(hooks);
+
+  test('Drag works with one item', async function (assert) {
+    this.items = ['Uno'];
+
+    this.update = (items) => {
+      set(this, 'items', items);
+    };
+
+    await render(hbs`
+      <ol id="test-list" {{sortable-group onChange=this.update}}>
+        {{#each this.items as |item|}}
+          <li data-test-item {{sortable-item model=item}}>{{item}}</li>
+        {{/each}}
+      </ol>
+    `);
+
+    await drag('mouse', '[data-test-item]', () => {
+      return { dy: 10 };
+    });
+
+    assert.equal(contents('#test-list'), 'Uno');
+  });
+
+  function contents(selector) {
+    return find(selector).textContent.replace(/⇕/g, '').replace(/\s+/g, ' ').replace(/^\s+/, '').replace(/\s+$/, '');
+  }
+});