src/History.js
function (binding) {
    var historyBinding = getHistoryBinding(binding);
    var undo = historyBinding.get('undo');
    return !!undo && !undo.isEmpty();
  }
function (binding) {
    var historyBinding = getHistoryBinding(binding);
    var undo = historyBinding.get('undo');
    return !!undo && !undo.isEmpty();
  }
function ( binding ) { var historyBinding = getHistoryBinding ( binding ) ; var undo = historyBinding . get ( 'undo' ) ; return ! ! undo && ! undo . isEmpty ( ) ; }
Check if history has undo information.
@param {Binding} binding binding
@returns {Boolean}
@memberOf History
Check if history has undo information .