我同时使用vuex和vuejs 2。

我是vuex的新手,我想看一个商店变量的变化。

我想在我的vue组件中添加手表功能

这是我目前所拥有的:

import Vue from 'vue';
import {
  MY_STATE,
} from './../../mutation-types';

export default {
  [MY_STATE](state, token) {
    state.my_state = token;
  },
};

我想知道my_state是否有任何变化

我怎么看店。My_state在我的vuejs组件?


当前回答

我想尽了一切办法让它运转起来。

理论

我发现,出于某种原因,对$store对象的更改不一定会触发.watch方法。我的解决办法是

Store Create a complex data set which should but doesn't propagate changes to a Component Create an incrementing counter in the state to act as a flag, which does propagate changes to a Component when watched Create a method in $store.mutators to alter the complex dataset and increment the counter flag Component Watch for changes in the $store.state flag. When change is detected, update locally relevant reactive changes from the $store.state complex data set Make changes to the $store.state's dataset using our $store.mutators method

实现

它的实现是这样的:

商店

let store = Vuex.Store({
  state: {
    counter: 0,
    data: { someKey: 0 }
  },
  mutations: {
    updateSomeKey(state, value) {
      update the state.data.someKey = value;
      state.counter++;
    }
  }
});

组件

  data: {
    dataFromStoreDataSomeKey: null,
    someLocalValue: 1
  },
  watch: {
    '$store.state.counter': {
        immediate: true,
        handler() {
           // update locally relevant data
           this.someLocalValue = this.$store.state.data.someKey;
        }
     }
  },
  methods: {
    updateSomeKeyInStore() { 
       this.$store.commit('updateSomeKey', someLocalValue);
  }

可运行演示

这很复杂,但基本上我们在这里观察一个要更改的标志,然后更新本地数据以反映存储在$状态中的对象的重要更改

Vue.config.devtools = false const store = new Vuex.Store({ state: { voteCounter: 0, // changes to objectData trigger a watch when keys are added, // but not when values are modified? votes: { 'people': 0, 'companies': 0, 'total': 0, }, }, mutations: { vote(state, position) { state.votes[position]++; state.voteCounter++; } }, }); app = new Vue({ el: '#app', store: store, data: { votesForPeople: null, votesForCompanies: null, pendingVote: null, }, computed: { totalVotes() { return this.votesForPeople + this.votesForCompanies }, peoplePercent() { if (this.totalVotes > 0) { return 100 * this.votesForPeople / this.totalVotes } else { return 0 } }, companiesPercent() { if (this.totalVotes > 0) { return 100 * this.votesForCompanies / this.totalVotes } else { return 0 } }, }, watch: { '$store.state.voteCounter': { immediate: true, handler() { // clone relevant data locally this.votesForPeople = this.$store.state.votes.people this.votesForCompanies = this.$store.state.votes.companies } } }, methods: { vote(event) { if (this.pendingVote) { this.$store.commit('vote', this.pendingVote) } } } }) <script src="https://cdn.jsdelivr.net/npm/vue@2.6.12"></script> <script src="https://unpkg.com/vuex@3.5.1/dist/vuex.js"></script> <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/css/bootstrap.min.css"> <div id="app"> <form @submit.prevent="vote($event)"> <div class="form-check"> <input class="form-check-input" type="radio" name="vote" id="voteCorps" value="companies" v-model="pendingVote" > <label class="form-check-label" for="voteCorps"> Equal rights for companies </label> </div> <div class="form-check"> <input class="form-check-input" type="radio" name="vote" id="votePeople" value="people" v-model="pendingVote" > <label class="form-check-label" for="votePeople"> Equal rights for people </label> </div> <button class="btn btn-primary" :disabled="pendingVote==null" >Vote</button> </form> <div class="progress mt-2" v-if="totalVotes > 0" > <div class="progress-bar" role="progressbar" aria-valuemin="0" :style="'width: ' + peoplePercent + '%'" :aria-aluenow="votesForPeople" :aria-valuemax="totalVotes" >People</div> <div class="progress-bar bg-success" role="progressbar" aria-valuemin="0" :style="'width: ' + companiesPercent + '%'" :aria-valuenow="votesForCompanies" :aria-valuemax="totalVotes" >Companies</div> </div> </div>

其他回答

Vue手表处于字符串状态

状态:

$store.state.local_store.list_of_data

内部组件

  watch: {
       
       '$store.state.local_store.list_of_data':{//<----------your state call in string
        handler(){
            console.log("value changeing in party sales entry"); //<---do your stuff here
        },
        deep:true
       }

    },

如上所述,直接在商店中观察变化并不是一个好主意

但在一些非常罕见的情况下,它可能对某人有用,所以我将留下这个答案。其他情况请参见@gabriel-robert answer

你可以通过州政府,$watch。将此添加到组件中创建的(或需要执行此方法的地方)方法中

this.$store.watch(
    function (state) {
        return state.my_state;
    },
    function () {
        //do something on data change
    },
    {
        deep: true //add this if u need to watch object properties change etc.
    }
);

详情:https://vuex.vuejs.org/api/#watch

这是为所有的人,不能解决他们的问题与getter,实际上真的需要一个监视器,例如,与非Vue第三方的东西(见Vue监视器何时使用监视器)。

Vue组件的监视器和计算值也都适用于计算值。所以vuex也没有什么不同:

import { mapState } from 'vuex';

export default {
    computed: {
        ...mapState(['somestate']),
        someComputedLocalState() {
            // is triggered whenever the store state changes
            return this.somestate + ' works too';
        }
    },
    watch: {
        somestate(val, oldVal) {
            // is triggered whenever the store state changes
            console.log('do stuff', val, oldVal);
        }
    }
}

如果只是结合本地和全局状态,mapState的文档也提供了一个例子:

computed: {
    ...mapState({
        // to access local state with `this`, a normal function must be used
        countPlusLocalState (state) {
          return state.count + this.localCount
        }
    }
})

我想尽了一切办法让它运转起来。

理论

我发现,出于某种原因,对$store对象的更改不一定会触发.watch方法。我的解决办法是

Store Create a complex data set which should but doesn't propagate changes to a Component Create an incrementing counter in the state to act as a flag, which does propagate changes to a Component when watched Create a method in $store.mutators to alter the complex dataset and increment the counter flag Component Watch for changes in the $store.state flag. When change is detected, update locally relevant reactive changes from the $store.state complex data set Make changes to the $store.state's dataset using our $store.mutators method

实现

它的实现是这样的:

商店

let store = Vuex.Store({
  state: {
    counter: 0,
    data: { someKey: 0 }
  },
  mutations: {
    updateSomeKey(state, value) {
      update the state.data.someKey = value;
      state.counter++;
    }
  }
});

组件

  data: {
    dataFromStoreDataSomeKey: null,
    someLocalValue: 1
  },
  watch: {
    '$store.state.counter': {
        immediate: true,
        handler() {
           // update locally relevant data
           this.someLocalValue = this.$store.state.data.someKey;
        }
     }
  },
  methods: {
    updateSomeKeyInStore() { 
       this.$store.commit('updateSomeKey', someLocalValue);
  }

可运行演示

这很复杂,但基本上我们在这里观察一个要更改的标志,然后更新本地数据以反映存储在$状态中的对象的重要更改

Vue.config.devtools = false const store = new Vuex.Store({ state: { voteCounter: 0, // changes to objectData trigger a watch when keys are added, // but not when values are modified? votes: { 'people': 0, 'companies': 0, 'total': 0, }, }, mutations: { vote(state, position) { state.votes[position]++; state.voteCounter++; } }, }); app = new Vue({ el: '#app', store: store, data: { votesForPeople: null, votesForCompanies: null, pendingVote: null, }, computed: { totalVotes() { return this.votesForPeople + this.votesForCompanies }, peoplePercent() { if (this.totalVotes > 0) { return 100 * this.votesForPeople / this.totalVotes } else { return 0 } }, companiesPercent() { if (this.totalVotes > 0) { return 100 * this.votesForCompanies / this.totalVotes } else { return 0 } }, }, watch: { '$store.state.voteCounter': { immediate: true, handler() { // clone relevant data locally this.votesForPeople = this.$store.state.votes.people this.votesForCompanies = this.$store.state.votes.companies } } }, methods: { vote(event) { if (this.pendingVote) { this.$store.commit('vote', this.pendingVote) } } } }) <script src="https://cdn.jsdelivr.net/npm/vue@2.6.12"></script> <script src="https://unpkg.com/vuex@3.5.1/dist/vuex.js"></script> <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/css/bootstrap.min.css"> <div id="app"> <form @submit.prevent="vote($event)"> <div class="form-check"> <input class="form-check-input" type="radio" name="vote" id="voteCorps" value="companies" v-model="pendingVote" > <label class="form-check-label" for="voteCorps"> Equal rights for companies </label> </div> <div class="form-check"> <input class="form-check-input" type="radio" name="vote" id="votePeople" value="people" v-model="pendingVote" > <label class="form-check-label" for="votePeople"> Equal rights for people </label> </div> <button class="btn btn-primary" :disabled="pendingVote==null" >Vote</button> </form> <div class="progress mt-2" v-if="totalVotes > 0" > <div class="progress-bar" role="progressbar" aria-valuemin="0" :style="'width: ' + peoplePercent + '%'" :aria-aluenow="votesForPeople" :aria-valuemax="totalVotes" >People</div> <div class="progress-bar bg-success" role="progressbar" aria-valuemin="0" :style="'width: ' + companiesPercent + '%'" :aria-valuenow="votesForCompanies" :aria-valuemax="totalVotes" >Companies</div> </div> </div>

我用了这种方法,它很有效:

store.js:

const state = {
  createSuccess: false
};

mutations.js

[mutations.CREATE_SUCCESS](state, payload) {
    state.createSuccess = payload;
}

actions.js

async [mutations.STORE]({ commit }, payload) {
  try {
    let result = await axios.post('/api/admin/users', payload);
    commit(mutations.CREATE_SUCCESS, user);
  } catch (err) {
    console.log(err);
  }
}

getters.js

isSuccess: state => {
    return state.createSuccess
}

在你使用state from store的组件中:

watch: {
    isSuccess(value) {
      if (value) {
        this.$notify({
          title: "Success",
          message: "Create user success",
          type: "success"
        });
      }
    }
  }

当用户提交表单时,action STORE将被调用,创建成功后,CREATE_SUCCESS突变将被提交。Turn createsuccsuccess为true,在组件中,监控器将看到值已更改并触发通知。

isSuccess应该匹配你在geters .js中声明的名称