A Simple Matter of Programming

function get(symbol) {
  return function(target) {
    return target[symbol];
  }
}
function set(symbol, value) {
  return function(target) {
    return target[symbol] = value;
  }
}

disableUnchecked: function() {
 this.checkboxes.reject(get('checked')).each(set('disabled', true));
}