From f857345451e2ad8ad39545f493ba880eff65de46 Mon Sep 17 00:00:00 2001
From: Dirk Holtwick <dirk.holtwick@gmail.com>
Date: Sat, 18 Dec 2021 18:26:32 +0100
Subject: [PATCH] Add canUndo/canRedo to UndoManager. Fixes #365

---
 src/utils/UndoManager.js | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/utils/UndoManager.js b/src/utils/UndoManager.js
index 391f82ac..b45439c5 100644
--- a/src/utils/UndoManager.js
+++ b/src/utils/UndoManager.js
@@ -282,4 +282,22 @@ export class UndoManager extends Observable {
     }
     return res
   }
+
+  /**
+   * Are undo steps available?
+   *  
+   * @return {boolean} `true` if undo is possible
+   */
+  canUndo() {
+    return this.undoStack.length > 0
+  }
+  
+  /**
+   * Are redo steps available?
+   *  
+   * @return {boolean} `true` if redo is possible
+   */
+  canRedo() {
+    return this.redoStack.length > 0
+  }
 }