AutoSave script

AutoSave.cs

using System.Linq;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.SceneManagement;

// Probably best to compile this to a DLL, or put in a folder with an
// assmebly definition set to editor only. Otherwise, put in an 
// Editor folder inside your project.

namespace ChrisDirkis.Utility.Editor {
    internal static class AutoSave {

        [InitializeOnLoadMethod]
        private static void RegisterAutoSaveCallback() {
            LastAutoSave = EditorApplication.timeSinceStartup;
            EditorApplication.update += AutoSaveCallback;
            EditorApplication.playModeStateChanged += OnPlayModeStateChanged;
        }

        private const double TimeBetweenSaves = 5 * 60;
        private static double LastAutoSave;

        private static void AutoSaveCallback() {
            if (!EditorApplication.isPlayingOrWillChangePlaymode && LastAutoSave + TimeBetweenSaves < EditorApplication.timeSinceStartup) {
                LastAutoSave = EditorApplication.timeSinceStartup;
                Save();
            }
        }

        private static void OnPlayModeStateChanged(PlayModeStateChange stateChange) {
            if (stateChange == PlayModeStateChange.ExitingEditMode) {
                Save();
            }
        }

        private static void Save() {
            AssetDatabase.SaveAssets();
            Debug.Log("Saved assets");

            var dirtyScenes = Enumerable.Range(0, SceneManager.sceneCount)
                .Select(SceneManager.GetSceneAt)
                .Where(s => s.isLoaded && s.isDirty)
                .ToList();
            EditorSceneManager.SaveOpenScenes();
            if (dirtyScenes.Count > 0) {
                Debug.Log($"Saved scenes: {string.Join(", ", dirtyScenes.Select(s => s.name))}");
            }
        }
    }
}