神奇的props

  props: {
    deliver: {
      type: Object,
      default: () => {
        return {};
      },
    },
  },

deliver {}

  props: {
    deliver: {
      type: Object,
      default: () => {},
    },
  },

deliver undefined

PS：昨天看了ES6写法，箭头函数还可以这么写
加小括号它就能识别出这玩意是对象OR空数组了！

  props: {
    deliver: {
      type: Object,
      default: () => ({})
    },
  },