const getters = {style:state => state.style}

computed: {
doneTodosCount () {
  return this.$store.getters.doneTodosCount}

import { mapGetters } from 'vuex'
computed: {
  // 使用對象展開運算符將 getters 混入 computed 對象中
  ...mapGetters([
  'doneTodosCount',
  'anotherGetter',])}
 //給getter屬性換名字
 mapGetters({
 // 映射 this.doneCount 為 store.getters.doneTodosCount
 doneCount: 'doneTodosCount'
})

  function `wrapGetters` (store, moduleGetters, modulePath) {
   Object.keys(moduleGetters).forEach(getterKey => {
      // 遍歷先所有的getters
    const rawGetter = moduleGetters[getterKey]
    if (store._wrappedGetters[getterKey]) {
     console.error(`[vuex] duplicate getter key: ${getterKey}`)
      // getter的key不允許重復(fù)，否則會報錯
     return
    }
    store._wrappedGetters[getterKey] = function `wrappedGetter` (store{
      // 將每一個getter包裝成一個方法，并且添加到store._wrappedGetters對象中，
      return rawGetter(
       //執(zhí)行g(shù)etter的回調(diào)函數(shù)，傳入三個參數(shù)，(local state,store getters,rootState)
      getNestedState(store.state, modulePath), // local state
       //根據(jù)path查找state上嵌套的state 
      store.getters, 
        // store上所有的getters
      store.state 
         // root state)}}) 
   }
   
   //根據(jù)path查找state上嵌套的state 
  function `getNestedState` (state, path) {
     return path.length
      ? path.reduce((state, key) => state[key], state): state}