missing files

Author: willmcgugan

src/textual/_unique.py

@@ -0,0 +1,15 @@
+"""A utility function to de-duplicate iterables while preserving order."""
+
+from __future__ import annotations
+
+from itertools import chain
+from typing import Iterable, TypeVar
+
+T = TypeVar("T")
+
+
+def unique_ordered(*widgets: Iterable[T]) -> list[T]:
+    """Converts a number of iterables of an object in to a list
+    where each value appears only once, while preserving order."""
+    unique_objects = list(dict.fromkeys(chain(*widgets)))
+    return unique_objects

tests/test_unique.py

@@ -0,0 +1,23 @@
+from textual._unique import unique_ordered
+
+
+def test_unique_ordered():
+    """Test result is both unique and the same order as given."""
+    assert unique_ordered() == []
+    assert unique_ordered([1]) == [1]
+    assert unique_ordered([1, 1, 1]) == [1]
+    assert unique_ordered([1], [2], [3]) == [1, 2, 3]
+    assert unique_ordered([1, 2], [2], [3, 1]) == [1, 2, 3]
+    assert unique_ordered([3, 1], [2], [1]) == [3, 1, 2]
+    assert unique_ordered([10, 9, 8, 7, 6, 5], [8, 7, 6, 5, 4], [5, 4, 3, 2, 1]) == [
+        10,
+        9,
+        8,
+        7,
+        6,
+        5,
+        4,
+        3,
+        2,
+        1,
+    ]