vuex工作圖示.png

• State對(duì)象：給Vue Component提供數(shù)據(jù)狀態(tài)，this.$store.state.name、...mapState(['name']) + computed
• gettings對(duì)象：對(duì)State里面的數(shù)據(jù)進(jìn)一步加工，this.$store.getters.name、...mapGetters(['name']) + computed
• Mutation對(duì)象：改變state狀態(tài)的方法集合，this.$store.commit('方法名',參數(shù))、...mapMutations(['name']) + methods
• Actions對(duì)象：處理異步數(shù)據(jù)，this.$store.dispatch('方法名',參數(shù))

1. 不使用Vuex實(shí)現(xiàn)Tab功能

關(guān)于Tab的實(shí)現(xiàn)：理想狀態(tài)下，"選擇層Tab + 展示層Current"，就夠了。但是，由于沒(méi)有公共狀態(tài)存儲(chǔ)的地方，只能借助父組件App，進(jìn)行tabIndex屬性的傳遞通信，很麻煩。所以說(shuō)，兄弟組件之間的通信還是Vuex比較適合

知識(shí)點(diǎn)1：動(dòng)態(tài)改變class類(lèi)的方式Array
知識(shí)點(diǎn)2：父子組件的通信派發(fā)事件this.$emit、props

# 子組件Tab: 存放Tab組件樣式的地方
<template>
    <div>
        <a href="javascript:;" @click="clickTab(1)" :class="['router', { current: tabIndex == 1 }]">選項(xiàng)1</a>
        <a href="javascript:;" @click="clickTab(2)" :class="['router', { current: tabIndex == 2 }]">選項(xiàng)2</a>
        <a href="javascript:;" @click="clickTab(3)" :class="['router', { current: tabIndex == 3 }]">選項(xiàng)3</a>
        <a href="javascript:;" @click="clickTab(4)" :class="['router', { current: tabIndex == 4 }]">選項(xiàng)4</a>
    </div>
</template>

<script>
export default {
    name: "tab",
    props: {
        tabIndex: Number,
    },
    methods: {
        clickTab(index) {
            // 自定義派發(fā)事件，監(jiān)聽(tīng)Tab的改變（子組件向父組件通信）
            this.$emit("clickTab", index);
        },
    },
};
</script>

<style scoped>
.router {
    text-decoration: none;
    color: #000;
    margin-right: 10px;
}
.current {
    color: aqua;
}
</style>

# 父組件：控制Tab邏輯的地方
<template>
    <div id="app">
        <Tab :tabIndex="tabIndex" @clickTab="changeTab"></Tab>
        <Current :tabIndex="tabIndex"></Current>
    </div>
</template>

<script>
import Tab from "@/components/tabs/index.vue";
import Current from "@/views/Current.vue";
export default {
    name: "App",
    data() {
        return {
            tabIndex: 1,
        };
    },
    components: {
        Tab,
        Current,
    },
    methods: {
        changeTab(index) {
            this.tabIndex = index;
        },
    },
   
};
</script>

# 子組件Current，展示Tab內(nèi)容的地方
<template>
    <div>頁(yè)面{{ tabIndex }}</div>
</template>

<script>
export default {
    name: "Current",
    props: {
        tabIndex: Number,
    },
};
</script>

2. 使用Vuex重寫(xiě)Tab功能

將tabIndex屬性，以及操作tabIndex屬性的方法，統(tǒng)一存儲(chǔ)到Vuex當(dāng)中，然后，在"選擇層Tab + 展示層
Current"，就夠了，跟App.vue沒(méi)關(guān)系了。

知識(shí)點(diǎn)：如何在Vue組件當(dāng)中調(diào)用Vuex里面的數(shù)據(jù)和方法？...mapState(['name'])、...mapMutations(['name'])

# store.js，聲明數(shù)據(jù)、以及操作數(shù)據(jù)方法
import Vue from "vue";
import Vuex from "vuex";

Vue.use(Vuex);

export default new Vuex.Store({
    state: {
        tabIndex: 1,
        test: "選項(xiàng)4"
    },
    mutations: {
        setTabIndex(state, index) {
            state.tabIndex = index;
        }
    }
});

# 子組件Tab: 存放Tab組件樣式的地方，并調(diào)用邏輯方法
<template>
    <div>
        <a href="javascript:;" @click="setTabIndex(1)" :class="['router', { current: tabIndex == 1 }]">選項(xiàng)1</a>
        <a href="javascript:;" @click="setTabIndex(2)" :class="['router', { current: tabIndex == 2 }]">選項(xiàng)2</a>
        <a href="javascript:;" @click="setTabIndex(3)" :class="['router', { current: tabIndex == 3 }]">選項(xiàng)3</a>
        <a href="javascript:;" @click="setTabIndex(4)" :class="['router', { current: tabIndex == 4 }]">{{ test }}</a>
    </div>
</template>


<script>
import { mapState, mapMutations } from "vuex";
export default {
    name: "tab",
    computed: {
        // 輔助方法mapState，拿到State對(duì)象里面的數(shù)據(jù)
        // ...mapState(["tabIndex", "test"]),
        tabIndex() {
            return this.$store.state.tabIndex;
        },
        test() {
            return this.$store.state.test;
        },
    },
    methods: {
        // 輔助方法mapMutations，拿到Mutations對(duì)象里面的方法
        // ...mapMutations(["setTabIndex"]),
        setTabIndex(index) {
            this.$store.commit("setTabIndex", index);
        },
    },
};
</script>

<style scoped>
.router {
    text-decoration: none;
    color: #000;
    margin-right: 10px;
}
.current {
    color: aqua;
}
</style>

#父組件App.vue
<template>
    <div id="app">
        <Tab></Tab>
        <Current></Current>
    </div>
</template>

<script>
import Tab from "@/components/tabs/index.vue";
import Current from "@/views/Current.vue";
export default {
    name: "App",
    components: {
        Tab,
        Current,
    },
};
</script>

#子組件，展示內(nèi)容區(qū)
<template>
    <div>頁(yè)面{{ tabIndex }}</div>
</template>

<script>
import { mapState } from "vuex";
export default {
    name: "Current",
    computed: {
        ...mapState(["tabIndex"]),
    },
};
</script>

3.actions處理異步數(shù)據(jù)dispatch、 context.commit()

問(wèn)題：如何將接口請(qǐng)求到的數(shù)據(jù)存儲(chǔ)到Vuex里面，并渲染到Vue組件當(dāng)中？
第一步：定義actions方法獲取異步數(shù)據(jù)
第二步：調(diào)用mutations方法將異步數(shù)據(jù)存到state里面
第三步：vue components拿著state里面的數(shù)據(jù)渲染

# 前提：Express API
# // http://localhost:3000/api/test?name=小明&age=18

module.exports = (app) => {
    var express = require("express");
    var router = express.Router();

    router.get("/test", (req, res) => {
        if ("小明" == req.query.name && 18 == req.query.age) {
            res.send("我是小明，今年18");
        } else {
            res.send("hello world");
        }
    });

    // 掛載router對(duì)象
    app.use("/api", router);
};

# vuex定義異步請(qǐng)求、數(shù)據(jù)存儲(chǔ)等方法 

import Vue from "vue";
import Vuex from "vuex";

import { axios } from "@/libs/https.js";
Vue.use(Vuex);

export default new Vuex.Store({
    state: {
        expressText: ""
    },
    mutations: {
        setExpressText(state, text) {
            state.expressText = text;
        }
    },
    actions: {
        // context上下文對(duì)象包含commit屬性、payload接受一個(gè)對(duì)象參數(shù)
        getData(context, payload) {
            axios.get(`/api/test?name=${payload.name}&age=${payload.age}`).then(res => {
                context.commit("setExpressText", res);
            });
        }
    }
});

#  actions function調(diào)用、以及數(shù)據(jù)渲染 
<template>
    <div id="app">
        {{ expressText }}
    </div>
</template>

<script>
import { mapState } from "vuex";
export default {
    name: "App",
    computed: {
        ...mapState(["expressText"]),
    },
    mounted() {
        this.$store.dispatch("getData", { name: "小明", age: 18 });
    },
};
</script>