code: function onTypingStart( undoManager ) {
  		// It's safe to now indicate typing state.
  		undoManager.typing = true;
  
  		// Manually mark snapshot as available.
  		undoManager.hasUndo = true;
  		undoManager.hasRedo = false;
  
  		undoManager.onChange();
  	}
docs: Helper method called when undoManager.typing val was changed to true.