Backbone中的es6类

Question

我正在学习code sample of es6 with Backbone。我对以下代码感到困惑：

class TodoView extends View {
  constructor(options) {
    this.tagName = 'li';
    this.template = _.template($('#item-template').html());
    this.input = '';
    this.events = {
      'click .toggle': 'toggleCompleted',
      'dbclick label': 'edit',
      'click .destroy': 'clear',
      'keypress .edit': 'updateOnEnter',
      'blur .edit': 'close'
    };

    super(options);

    this.listenTo(this.model, 'change', this.render);
    this.listenTo(this.model, 'destroy', this.remove);
    this.listenTo(this.model, 'visible', this.toggleVisible);
  }

我有一些问题：

1，super(options)的位置是否重要？ 2，我应该将this.listenTo()移至initialize()吗？ 3，following codes怎么样？

constructor() {
    super({
        tagName:  'li',

        template: _.template(todosTemplate),

        events: {
            'click .toggle':    'toggleCompleted',
            'dblclick label':   'edit',
            'click .destroy':   'clear',
            'keypress .edit':   'updateOnEnter',
            'keydown .edit':    'revertOnEscape',
            'blur .edit':       'close'
        },
    });
}