手写 vuex

插件固定写法

let Vue = null
const install=(v)=>{
    Vue = v

}
export default{
    install
}

混入

const install=(v)=>{
    Vue = v
    Vue.mixin({// 混入 以后子组件都可以使用$store 访问 
        beforeCreate() {
            //判断是否为根节点，根节点会挂载store
            if(this.$options && this.$options.store){
                this.$store = this.$options.store
            }else{
                this.$store = this.$parent && this.$parent.$store
            }
        },
    })

}

创建 Store

由于需要使用 new Vuex.Store 来创建，所以 Vuex 中要包含Store

class Store{
    constructor(options){
        
    }
}

如何实现响应式

可以借助vue 响应式来实现 创建一个vue 实例，将store 放在data 方法中

class Store{
    constructor(options){
        this.vm = new Vue({
            data:{
                state:options.state
            }
        })

    }
    get state(){
        return this.vm.state
    }

}

实现getter

    let getters = options.getters || {}
    this.getters = {}
    Object.keys(getters).forEach(getName=>{
        Object.defineProperty(this.getters,getName,{
            get:()=>{return getters[getName](this.state)}
        })
    })   

实现mutations commit

    let mutations = options.mutations || {}
    this.mutations = {}
    Object.keys(mutations).forEach(mutationName=>{
        this.mutations[mutationName] = payload=>{
            mutations[mutationName](this.state,payload)
        }
    })  
    commit = (method, payload) => {
        this.mutations[method](payload)
    }    

实现 actions dispatch

    let actions = options.actions || {}
    this.actions = {}
    Object.keys(actions).forEach(actionName => {
        this.actions[actionName] = payload => {
            actions[actionName](this, payload)
        }
    })
    dispatch = (method, payload)=>{
        this.actions[method](payload)
    }

完整代码

let Vue = null
class Store {
    constructor(options) {
        this.vm = new Vue({
            data(){
                return  {
                state: options.state
            }
            }
        })
        let getters = options.getters || {}
        this.getters = {}
        Object.keys(getters).forEach(getName => {
            Object.defineProperty(this.getters, getName, {
                get: () => { return getters[getName](this.state) }
            })
        })

        let mutations = options.mutations || {}
        this.mutations = {}
        Object.keys(mutations).forEach(mutationName => {
            this.mutations[mutationName] = payload => {
                mutations[mutationName](this.state, payload)
            }
        })
        let actions = options.actions || {}
        this.actions = {}
        Object.keys(actions).forEach(actionName => {
            this.actions[actionName] = payload => {
                actions[actionName](this, payload)
            }
        })

    }
    commit = (method, payload) => {
        this.mutations[method](payload)
    }
    dispatch = (method, payload)=>{
        this.actions[method](payload)
    }

    get state() {
        return this.vm.state
    }

}

const install = (v) => {
    Vue = v
    Vue.mixin({// 混入 以后子组件都可以使用$store 访问 
        beforeCreate() {
            //判断是否为根节点，根节点会挂载store
            if (this.$options && this.$options.store) {
                this.$store = this.$options.store
            } else {
                this.$store = this.$parent && this.$parent.$store
            }
        },
    })

}
export default {
    install,
    Store
}

简单来讲就是将const store = new Vuex.Store({
.....
})内部传递的参数在 Vuex 中实现一下