简述vuex实现原理

vuex实现原理实际上是通过Vue的实例化来实现

这里通过计数器来说明
简述vuex实现原理_第1张图片

首先实例化两个Vue对象,通过他测试是否能统一管理状态#root和 #root2

 new Vue({
        el:'#root',
        computed:{
            data(){
                return this.$store.state.count
            }
        },

    });
    new Vue({
        el:'#root2',
        computed:{
            data2(){
                return this.$store.state.count
            }
        }
    });

接下就是实例化一个Vue对象来统一管理状态

function registerPlugin(Vue){
        const myVuex  = {};
        myVuex._vm = new Vue({ // 实例化一个vue对象
            data(){
                return {
                    count : 0
                }
            }
        });
        myVuex.state = myVuex._vm;
        myVuex.dispatch = (name)=>{
            console.log(myVuex);
            myVuex.actions[name]()
        };
        myVuex.actions =  {
            //调用mutation
            addPoint:()=>{
                myVuex.mutations.ADDCOUNT()
            },
            reducePoint:()=>{
                myVuex.mutations.REDUCECOUNT()
            }
        };
        myVuex.mutations = {
            //改变state状态
            ADDCOUNT(){
                  myVuex.state.count += 1
            },
            REDUCECOUNT(){
                  myVuex.state.count-=1
            }
        };
        function init(){
            this.$store = myVuex;   //this指向Vue对象
        }
        Vue.mixin({ //每当实例化Vue对象时都会调用
            beforeCreate:init // 注意这里init不能加括号,加上()后赋值给beforeCrete是函数的返回值,返回值为空则赋值的是undefined,,
                                //另外在加上括号赋值后,init函数将回在赋值的同时被调用,其this指向也将指向window !!!!!
        });
    }
    Vue.use(registerPlugin)

接下来通过调用this.$store.dispatch('addPoint');就可以改变统一管理的状态值

全部代码:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
    <p id="root">{{data}}</p>
    <p id="root2">{{data2}}</p>
    <div id="root3">
        <button  @click="addPoint()">+</button>
        <button  @click="reducePoint()">-</button>
    </div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
    function registerPlugin(Vue){
        const myVuex  = {};
        myVuex._vm = new Vue({ // 实例化一个vue对象
            data(){
                return {
                    count : 0
                }
            }
        });
        myVuex.state = myVuex._vm;
        myVuex.dispatch = (name)=>{
            console.log(myVuex);
            myVuex.actions[name]()
        };
        myVuex.actions =  {
            //调用mutation
            addPoint:()=>{
                myVuex.mutations.ADDCOUNT()
            },
            reducePoint:()=>{
                myVuex.mutations.REDUCECOUNT()
            }
        };
        myVuex.mutations = {
            //改变state状态
            ADDCOUNT(){
                  myVuex.state.count += 1
            },
            REDUCECOUNT(){
                  myVuex.state.count-=1
            }
        };
        function init(){
            this.$store = myVuex;   //this指向Vue对象
        }
        Vue.mixin({ //每当实例化Vue对象时都会调用
            beforeCreate:init // 注意这里init不能加括号,加上()后赋值给beforeCrete是函数的返回值,返回值为空则赋值的是undefined,,
                                //另外在加上括号赋值后,init函数将回在赋值的同时被调用,其this指向也将指向window !!!!!
        });
    }
    Vue.use(registerPlugin)


    new Vue({
        el:'#root',
        computed:{
            data(){
                return this.$store.state.count
            }
        },

    });
    new Vue({
        el:'#root2',
        computed:{
            data2(){
                return this.$store.state.count
            }
        }
    });
    new Vue({
        el:'#root3',
        methods:{
            addPoint(){
                this.$store.dispatch('addPoint');
            },
            reducePoint(){
                this.$store.dispatch('reducePoint');
            }
        }
    })
</script>
</body>
</html>

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