ractivejs观察init vs set / push / update

Question

在此代码示例中， 在init上，针对每个元素触发了观察，即使没有＆＃34;价格＆＃34;但是没有触发任何其他方法，为什么？

var _deals = [
    {
        prices: [
            {
                id: 1,
                deal_id: 1,
                guests_from: 100,
                guests_to: 200,
                price: 250
            }
        ]
    },
    {
        prices: []
    },
    {}  // this fires also, Why?
];


var deals = [], // app database
    dealsGuy;   // app instance


deals = _deals;


// create our app view

dealsGuy = new Ractive({
  el: '#app_block',
  template: '#app-template',
  noIntro: true, // disable transitions during initial render

  data: {
    deals: deals
  },

  decorators: {
    datepicker: datepickerDecorator
  }
});   

dealsGuy.observe('deals.*.prices', function (newValue, oldValue, keypath) {

    console.log( 'observe', keypath );

    if( newValue === void 0 || newValue.length <= 0 ){

        this.set(keypath,[{}]);
    }
});

dealsGuy.push('deals', {}); // does not fire 'deals.*.prices'

Answer 1

我想这是由于在初始化和更新期间考虑事情的一个细微差别。

始终触发初始化观察（即使值为undefined），而只有在值实际发生变化时才会触发更新。