# Store

在 Nuxt 專案中以 TypeScript 使用 store 的方法有很多種。

# Class-based

# vuex-module-decorators

最受歡迎的使用方式是 vuex-module-decorators - 查看 guide.

為了與 Nuxt 一起使用,有幾個主要的限制條件:

  1. 你的模組必須和 stateFactory: true 一起使用,例如:

    ~/store/mymodule.ts:

    import { Module, VuexModule, Mutation } from 'vuex-module-decorators'
    
    @Module({
      name: 'mymodule',
      stateFactory: true,
      namespaced: true,
    })
    class MyModule extends VuexModule {
      wheels = 2
    
      @Mutation
      incrWheels(extra) {
        this.wheels += extra
      }
    
      get axles() {
        return this.wheels / 2
      }
    }
    
  2. 如果你不想要在每個元件中初始化並存取 store,你可以使用 initialiser plugin, 例如: ~/store/index.ts:

    import { Store } from 'vuex'
    import { initialiseStores } from '~/utils/store-accessor'
    
    const initializer = (store: Store<any>) => initialiseStores(store)
    
    export const plugins = [initializer]
    export * from '~/utils/store-accessor'
    
  3. 如果你想要存取 Nuxt app 實例,你會需要對 plugin 做類似的事,例如: ~/plugins/axios-accessor.ts:

    import { Plugin } from '@nuxt/types'
    import { initializeAxios } from '~/utils/api'
    
    const accessor: Plugin = ({ $axios }) => {
      initializeAxios($axios)
    }
    
    export default accessor
    

    ~/utils/api.ts:

    import { NuxtAxiosInstance } from '@nuxtjs/axios'
    
    let $axios: NuxtAxiosInstance
    
    export function initializeAxios(axiosInstance: NuxtAxiosInstance) {
      $axios = axiosInstance
    }
    
    export { $axios }
    

    ~/store/users.ts:

    import { Module, VuexModule, Action, Mutation } from 'vuex-module-decorators'
    import { $axios } from '~/utils/api'
    import { User } from '~/types'
    
    @Module({
      name: 'users',
      stateFactory: true,
      namespaced: true,
    })
    class UserModule extends VuexModule {
      users: User[] = []
    
      @Mutation
      setUsers(users: User[]) {
        this.users = users
      }
    
      @Action
      async getUsers() {
        const users = $axios.$get('/users')
        this.setUsers(users)
      }
    }
    

# vuex-class-component

vuex-class-component 的語法相似於 vuex-module-decorators,是一個有望成為以 class 為基底的 Nuxt store。儘管他還沒有和 Nuxt 非常相容,但不久前發佈了新的 API,暫時的替代方案是使用模組的 decorator:

@Module({ namespacedPath: 'foo' })
export default class extends VuexModule {}

查看 這個問題 來追蹤目前在 Nuxt 遇到的相容性問題狀態。

# 原生 Vanilla

# 基本型別

當你在使用 store 時,Vuex 提供了非常基本的型別。你可以使用他們幫助你定義你的 store。例如:

~/store/index.ts:

import { GetterTree, ActionTree, MutationTree } from 'vuex'

export const state = () => ({
  things: [] as string[],
  name: 'Me',
})

export type RootState = ReturnType<typeof state>

export const getters: GetterTree<RootState, RootState> = {
  name: state => state.name,
}

export const mutations: MutationTree<RootState> = {
  CHANGE_NAME: (state, newName: string) => (state.name = newName),
}

export const actions: ActionTree<RootState, RootState> = {
  fetchThings({ commit }) {
    const things = this.$axios.$get('/things')
    console.log(things)
    commit('CHANGE_NAME', 'New name')
  },
}

你也會在模組當中使用一模一樣的方法。例如:

~/store/anotherModule.ts:

import { GetterTree, ActionTree, MutationTree } from 'vuex'
import { RootState } from '~/store'

export const state = () => ({
  more: 3,
})

export type AnotherModuleState = ReturnType<typeof state>

export const getters: GetterTree<AnotherModuleState, RootState> = {
  evenMore: state => state.more + 5,
  nameAndMore: (state, getters, rootState) => `${rootState.name}: ${state.more}`,
}

export const actions: ActionTree<AnotherModuleState, RootState> = {
  printRootState({ rootState }) {
    console.log('accessing rootState:', rootState.name)
  },
}

# 存取 store

# nuxt-typed-vuex

Vuex 並沒有在你的應用程式當中提供型別給你,在 Nuxt app 中,你會得到一個沒有任何型別的 this.$store

有一個新項目 nuxt-typed-vuex - 和 guide - 皆在試圖解決這個問題。

# 自己來

或者你也可以使用自己提供的型別。

~/components/MyComponent.vue:

<script lang="ts">

import { Component, Vue } from 'nuxt-property-decorator'
import { getters, RootState } from '~/store'

@Component
export default class MyComponent extends Vue {
    get myThings() {
        return (this.$store.state as RootState).things
    }

    mounted() {
        const name = this.$store.getters['name'] as ReturnType<typeof getters.name>
    }
}