版权声明: https://blog.csdn.net/weixin_33768153/article/details/82842529
很多时候我们会有很多个页面,会有很多个reducer,那么我们写在一起的话不仅不方便维护,而且文件一会变得越来越臃肿,那怎么办呢,当然是写一个方法,然后处理这些琐碎的事情
combineReducers, 接受多个reducer,最后合并为一个reducer,然后返回这个合并后的对象
combineReducers.js
在redux下新建文件,combineReducers.js代码如下
/**
* 因为redux应用只能有一个仓库,只能有一个reducer,当我们写了很多个的时候就需要一个方法来合并
* 这个方法就是处理合并多个reducer合并成一个reducer
*/
export default function (reducers) {
// 返回一个函数,这个函数就是合并后的reducer
return function (state = {}, action) {
let newState = {}
// 迭代reducers的每一个属性
for (let key in reducers) {
// 拿到合并前的处理器函数,然后执行并运算
// 经过处理以后,
// key = counter(reducer)
// newState.key = reducers[key] // 这里赋值给newState的就是counter的reducer
// state是合并后的状态树
newState[key] = reducers[key](state[key], action)
}
return newState
}
}
- bindActionCreators.js
/**
* 我们不可能每次一个动作都手动大护法dispatch,这里方法主要是帮我们处理自动更新页面
* @param {object} actions 动作类型
* @param {fn} dispatch 派发动作的函数
*/
export default function (actions, dispatch) {
// 我们需要返回的状态
// actions = {add () {dispatch({type: ADD})}, minus () {dispatch({type: MINUS})}}
// let newActons = {}
// 这么写 不是很优雅
// for (let key in actions) {
// newActons[key] = () => dispatch(actions[key]())
// }
// return newActons
return Object.keys(actions).reduce((memo, key) => {
// memo[key] = (...args) => dispatch(actions[key]()) ...args 是方便我们后边传参
memo[key] = (...args) => dispatch(actions[key](...args))
return memo
}, {})
}
在redux/index.js导出该方法
import createStore from './createStore'
import bindActionCreators from './bindActionCreators'
import combineReducers from './combineReducers'
export {
createStore,
bindActionCreators,
combineReducers
}
compoents下修改
- Counter.js
import React from 'react';
import store from '../store'
import actions from '../store/actions/counter'
// 绑定action,自动派发事件给store
import {bindActionCreators} from '../redux'
let action = bindActionCreators(actions, store.dispatch)
export default class Counter extends React.Component {
state = store.getState().counter
componentDidMount() {
store.subscribe(() => this.setState({
number: store.getState().counter.number
}))
}
render () {
return (
<div>
<p>Counter: {this.state.number}</p>
{/* 传参调用方式 */}
<button onClick={() => action.add(1)}>+</button>
<button onClick={() => action.minus(2)}>-</button>
</div>
)
}
}
- Counter1.js
import React from 'react';
import store from '../store'
// 这里引入的action和Counter是不一样的
import actions from '../store/actions/counter1'
// 绑定action,自动派发事件给store
import {bindActionCreators} from '../redux'
let action = bindActionCreators(actions, store.dispatch)
export default class Counter extends React.Component {
state = store.getState().counter1
componentDidMount() {
store.subscribe(() => this.setState({
number: store.getState().counter1.number
}))
}
render () {
return (
<div>
<p>Counter: {this.state.number}</p>
<button onClick={() => action.add1(1)}>+</button>
<button onClick={() => action.minus1(2)}>-</button>
</div>
)
}
}
store目录下的修改
-
新建actions目录,并创建Counter.js, Counter1.js
- counter.js文件内容
/** * 抽离actions 单独管理 */ import { ADD, MINUS} from '../actions-types'; export default { add(playload) { return { type: ADD, playload} }, minus(playload) { return { type: MINUS, playload} } }
- counter1.js文件内容
/** * 抽离actions 单独管理 */ import { ADD1, MINUS1 } from '../actions-types'; export default { add1(playload) { return { type: ADD1, playload} }, minus1(playload) { return { type: MINUS1, playload} } }
-
新建reuders文件目录,并在该目录下创建两个处理器Counter.js, Counter1.js
- counter.js文件内容(这里处理counter 的action动作)
import { ADD, MINUS } from "../actions-types"; let initState ={number: 0} // 处理器 export default function reducer(state = initState, action) { switch (action.type) { // case ADD: // return { number: state.number + 1 } // break; // case MINUS: // return { number: state.number - 1 } // break; // 传参使用 case ADD: return {number: state.number + (action.playload || 1)} break; case MINUS: return {number: state.number - (action.playload || 1)} break; default: return state break; } }
- counter1.js文件内容(这里处理counter1 的action动作)
import { ADD1, MINUS1 } from "../actions-types"; let initState = {number: 0} // 处理器 export default function reducer(state = initState, action) { switch (action.type) { // case ADD: // return { number: state.number + 1 } // break; // case MINUS: // return { number: state.number - 1 } // break; // 传参使用 case ADD1: return {number: state.number + (action.playload || 1)} break; case MINUS1: return {number: state.number - (action.playload || 1)} break; default: return state break; } }
-
store/index.js文件修改
import counter from './counter'
import counter1 from './counter1'
import {combineReducers} from '../../redux'
import reducer from './counter1';
// 合并多个处理器为一个处理器
let reducers = combineReducers({
counter,
counter1
})
export default reducers
根目录下index.js的修改
import React from 'react';
import ReactDOM from 'react-dom';
import Conuter from './components/Counter'
import Conuter2 from './components/Counter2'
ReactDOM.render(<div>
<Conuter />
<Conuter2 />
</div>, document.getElementById('root'));
总结
到了这里,实现了简单的调用和多个reuducer合并后的操作,但是我们还是发现很多操作不人性化,后边继续优化
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