react useReducer

useReducer():Action钩子

import React, {useReducer} from 'react'

export default function UseReducer() {

const reducer = (state, action) => {

switch (action.type) {

case 'add':

return {count: state.count + 1};

default:

return {count: state.count};

}

}

const [state, dispatch] = useReducer(reducer, {count: 0})

const addcount = () => {

dispatch({

type: 'add'

})

}

return (

{state.count}

count++

)

}