第二十九章 使用消息订阅发布实现组件通信

npm install pubsub-js

import PubSub from 'pubsub-js'

PubSub.subscribe('List',function(msg, data){ console.log(msg, data)})

PubSub.publish('List',data)

PubSub.unsubscribe(this.token)

import React, { Component } from 'react'
import Search from './components/Search'
import List from './components/List'
export default class App extends Component {
  render() {
    return (
      <div className="container">
        <Search/>
        <List/>
    </div>
    )
  }
}

import React, { Component } from 'react'
import PubSubJs from 'pubsub-js'
export default class Search extends Component {
  searchHandle = () => {
    const {KeyVal:{value}} = this
    PubSubJs.publish('getSearchVal',value)
  }
  render() {
    return (
      <section className="jumbotron">
      <h3 className="jumbotron-heading">Search Github Users</h3>
      <div>
        <input ref={c=>this.KeyVal = c} type="text" placeholder="关键字"/>
      <button onClick={this.searchHandle}>Search</button>
      </div>
    </section>
    )
  }
}

import React, { Component } from 'react'
import PubSubJs from 'pubsub-js'
import axios from 'axios'
import './index.css'
export default class List extends Component {
  state = {
    users: [],
    isFirst: true,
    isLoading: false,
    err: '',
  }
  getSearchFunc = (msg, data) => {
    console.log('接收的信息', data)
    this.setState({ users: [], isFirst: false, isLoading: true })
    axios
      .get(`https://api.github.com/search/users?q=${data}`)
      .then(
        (res) => {
          this.setState({ users: res.data.items, isFirst: false, isLoading: false })
          console.log('请求成功了', res.data)
        },
        (err) => {
          console.log('请求失败了', err)
          this.setState({isFirst: false, isLoading: false,err:err.message })
        }
      )
      .catch(() => {})
  }
  componentDidMount() {
   this.token = PubSubJs.subscribe('getSearchVal', this.getSearchFunc)
  }
  componentWillUnmount() {
    PubSubJs.unsubscribe(this.token)
  }
  render() {
    const { users, isFirst, isLoading, err } = this.state
    return (
      <div className="row">
        {isFirst ? (
          <h2>欢迎搜索</h2>
        ) : isLoading ? (
          <h2>Loading...</h2>
        ) : err ? (
          <h3>{err}</h3>
        ) : (
          users.map((userObj) => {
            return (
              <div className="card" key={userObj.id}>
                <a href={userObj.html_url} target="_blank" rel="noreferrer">
                  <img
                    alt="头像"
                    src={userObj.avatar_url}
                    style={{ width: '100px' }}
                  />
                </a>
                <p className="card-text">{userObj.login}</p>
              </div>
            )
          })
        )}
      </div>
    )
  }
}

let obj = {a:{b:1}}
const { a } = obj // 传统的解构赋值
const { a:{b} } = obj // 连续的解构赋值
const { a:{b:value} } = obj // 连续解构赋值 + 重命名

async func () {
    try {
        const res = await fetch('url')
        const data = await res.json()
        console.log(data)
    } catch(error) {
        console.log(error)
    }
}