原始的redux

import { createStore } from 'redux';

//1.通过reducer新建store
//2.根据老的state和action 生成新的state

//下面这个函数其实就是reducer的作用
function counter(state=0,action){
    switch(action.type){
        case '加机关枪':
            return state+1
        case '减机关枪':
            return state-1
        default:
            return 10        
    }
}

//新建store
const store = createStore(counter);

const init = store.getState();
console.log(init)

function listener(){
    const current = store.getState();
    console.log(`现在有机枪${current}`)
}

//用subscribe监听每次修改情况
store.subscribe(listener)
//dispatch派发事件 传递action
store.dispatch({type:'加机关枪'});
store.dispatch({type:'加机关枪'});
store.dispatch({type:'减机关枪'});