From 21b3b3c9d13c54397ef822fd6f48d50e51bba29a Mon Sep 17 00:00:00 2001
From: Isaiah Odhner <isaiahodhner@gmail.com>
Date: Wed, 8 Aug 2018 14:57:45 -0400
Subject: [PATCH] Disable undo/redo buttons appropriately

---
 index.html     | 1 -
 src/app.coffee | 6 ++++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/index.html b/index.html
index fbbb990..d0f1cf7 100644
--- a/index.html
+++ b/index.html
@@ -109,7 +109,6 @@ <h2>Interactive Fretboard</h2>
 			<h2>Tablature Editor</h2>
 			<div class="controls">
 				<!-- TODO: icon buttons -->
-				<!-- TODO: disabled state when not hasUndo/hasRedo -->
 				<button id="undo">Undo</button>
 				<button id="redo">Redo</button>
 				<!-- (((multi-(line/row/string)) / (staff/stave)) (selection/cursor) [mode]) -->
diff --git a/src/app.coffee b/src/app.coffee
index c198e5a..e39d1d4 100644
--- a/src/app.coffee
+++ b/src/app.coffee
@@ -113,6 +113,12 @@ redo_button.addEventListener "click", ->
 	tablature_editor.editor.redo()
 	return
 
+tablature_editor.editor.on "input", ->
+	undo_manager = tablature_editor.editor.session.getUndoManager()
+	undo_button.disabled = not undo_manager.hasUndo()
+	redo_button.disabled = not undo_manager.hasRedo()
+	
+
 do update_multi_row_selection_mode = ->
 	tablature_editor.multi_row_selection_mode = multi_row_selection_mode_input.checked
 	return