Add ability to indent/un-indent multiple list items (#1642)

* Add ability to indent/un-indent multiple list items

* some improvement

* fix using unhang; add more test cases

* Adding changset for list indentation fix

.changeset/lemon-queens-pretend.md

@@ -0,0 +1,5 @@
+---
+'@udecode/plate-list': minor
+---
+
+Improved list item indentation when selection spans across different elements

packages/nodes/list/src/onKeyDownList.ts

@@ -2,13 +2,17 @@ import {
   getAboveNode,
   HotkeyPlugin,
   Hotkeys,
+  isCollapsed,
   KeyboardHandlerReturnType,
   PlateEditor,
+  select,
+  unhangRange,
   Value,
   WithPlatePlugin,
 } from '@udecode/plate-core';
 import isHotkey from 'is-hotkey';
 import { castArray } from 'lodash';
+import { Range } from 'slate';
 import { moveListItems, toggleList } from './transforms';
 
 export const onKeyDownList = <
@@ -20,16 +24,37 @@ export const onKeyDownList = <
 ): KeyboardHandlerReturnType => (e) => {
   const isTab = Hotkeys.isTab(editor, e);
   const isUntab = Hotkeys.isUntab(editor, e);
+
+  let workRange = editor.selection;
+
   if (editor.selection && (isTab || isUntab)) {
+    const { selection } = editor;
+
+    // Unhang the expanded selection
+    if (!isCollapsed(editor.selection)) {
+      const { anchor, focus } = Range.isBackward(selection)
+        ? { anchor: selection.focus, focus: selection.anchor }
+        : { anchor: selection.anchor, focus: selection.focus };
+
+      // This is a workaround for a Slate bug 
+      // See: https://github.com/ianstormtaylor/slate/pull/5039
+      anchor.offset = 0;
+      const unHungRange = unhangRange(editor, { anchor, focus });
+      if (unHungRange) {
+        workRange = unHungRange;
+        select(editor, unHungRange);
+      }
+    }
+
+    // check if we're in a list context.
     const listSelected = getAboveNode(editor, {
       at: editor.selection,
-      match: { type },
     });
 
-    if (listSelected) {
+    if (workRange && listSelected) {
       e.preventDefault();
-      moveListItems(editor, { increase: isTab });
-      return;
+      moveListItems(editor, { at: workRange, increase: isTab });
+      return true;
     }
   }