OldBlueWater/BlueWater/Assets/02.Scripts/Utility/HierarchySorter.cs

using UnityEngine;
using UnityEditor;
using System.Linq;

// ReSharper disable once CheckNamespace
namespace BlueWaterProject
{
    public class HierarchySorter : EditorWindow
    {
        [MenuItem("Tools/Sort Children by Name")]
        private static void SortChildrenByName()
        {
            if (Selection.activeTransform != null)
            {
                Undo.RecordObject(Selection.activeTransform.gameObject, "Sort Children by Name");

                var children = Selection.activeTransform.Cast<Transform>().OrderBy(t => t.name).ToList();
                for (var i = 0; i < children.Count; i++)
                {
                    children[i].SetSiblingIndex(i);
                }

                EditorUtility.SetDirty(Selection.activeTransform.gameObject);
            }
            else
            {
                Debug.LogError("No object selected in the hierarchy");
            }
        }
        
        [MenuItem("Tools/Sort Children of Selected Objects by Name")]
        private static void SortChildrenOfSelectedObjectsByName()
        {
            foreach (var parentTransform in Selection.transforms)
            {
                Undo.RecordObject(parentTransform.gameObject, "Sort Children by Name");

                var children = parentTransform.Cast<Transform>().OrderBy(t => t.name).ToList();
                for (var i = 0; i < children.Count; i++)
                {
                    children[i].SetSiblingIndex(i);
                }

                EditorUtility.SetDirty(parentTransform.gameObject);
            }
        }
    }
}