如何在React中直接使用Redux

import { createStore } from "redux";
import reducer from "./reducer";

const store = createStore(reducer)

export default store

export const CHANGE_NUM  = "change_num"

import { CHANGE_NUM } from "./constants"

const initialState = {
  counter: 10
}

export default function reducer(state = initialState, action) {
  switch(action.type) {
    case CHANGE_NUM:
      return {...state, counter: state.counter + action.num}
    default: 
      return state
  }
}

import { CHANGE_NUM } from "./constants"

export const changeNumAction = (num) => ({
  type: CHANGE_NUM,
  num
})

import React, { PureComponent } from 'react'
import store from '../store'
import { changeNumAction } from '../store/actionCreators'

export class Home extends PureComponent {
  constructor() {
    super()

    this.state = {
      counter: store.getState().counter
    }
  }

  // 核心一: 在componentDidMount中监听store的变化，当数据发生变化时重新设置 counter;
  componentDidMount() {
    store.subscribe(() => {
      const state = store.getState()
      this.setState({ counter: state.counter })
    })
  }

  // 核心二: 在发生点击事件时，调用store的dispatch来派发对应的action;
  changeNum(num) {
    store.dispatch(changeNumAction(num))
  }

  render() {
    const { counter } = this.state

    return (
      <div>
        <h2>Home</h2>
        <h2>当前计数: {counter} </h2>
        <button onClick={() => this.changeNum(1)}>+1</button>
        <button onClick={() => this.changeNum(5)}>+5</button>
      </div>
    )
  }
}

export default Home

import React, { PureComponent } from 'react'
import store from '../store'
import { changeNumAction } from '../store/actionCreators'

export class Profile extends PureComponent {
  constructor() {
    super()

    this.state = {
      counter: store.getState().counter
    }
  }

  componentDidMount() {
    store.subscribe(() => {
      const state = store.getState()
      this.setState({ counter: state.counter })
    })
  }

  changeNum(num) {
    store.dispatch(changeNumAction(num))
  }

  render() {
    const { counter } = this.state

    return (
      <div>
        <h2>Profile</h2>
        <h2>当前计数: {counter}</h2>
        <button onClick={() => this.changeNum(-1)}>-1</button>
        <button onClick={() => this.changeNum(-5)}>-5</button>
      </div>
    )
  }
}

export default Profile