解构赋值解释

看一段redux中的connect方法的参数
第一眼看上去蒙逼了吧

  ({ welcomeAndWorkplace: { currentUser, projectNotice, activities, radarData }, loading })
  => (
    {
      currentUser,
      projectNotice,
      activities,
      radarData,
      currentUserLoading: loading.effects['welcomeAndWorkplace/fetchUserCurrent'],
      projectLoading: loading.effects['welcomeAndWorkplace/fetchProjectNotice'],
      activitiesLoading: loading.effects['welcomeAndWorkplace/fetchActivitiesList'],
    }
  )

不过是解构赋值

一个更简单的demo来解释它
这是一个.vue文件
在data里return了

devicesInfo: {
  windowHeight: "111"
},

在onReady执行了解构这个值

  const {
      devicesInfo: { hehe }
  } = this._data;
    console.log(hehe, "[][][][]");    //undefined

这段程序解构了data里的devicesInfo然后复制给了{hehe}？不是的，打印出来是undefined
这样是先解构了devicesInfo然后复制给了haha

const { devicesInfo: haha } = this._data;

1. {ob: Observer}
   1. statusBarHeight:0
   2. windowHeight:(…)

而这种形式是又发生了一次解构

  const {
      devicesInfo: { windowHeight }
  } = this._data;
 console.log(windowHeight, "[][][][]");//111

事情很明了了

({ welcomeAndWorkplace: { currentUser, projectNotice, activities, radarData }, loading })

解构了传入的welcomeAndWorkplace，又解构了这个welcomeAndWorkplace，解构出了currentUser, projectNotice, activities, radarData，