23.react-router 路由

箭头函数扩展:

箭头函数：

functoin 函数名(参数){
   函数体
}

箭头函数：

一、把function删掉 ，
二、参数和{}之间加上 箭头=>

简写：

一、参数的简写：只有一个参数才能简写
二、函数体的简写：只有一条语句才能简写 exp:

var f = v => alert(1);

var show = (a,b)=> {
    alert(1); 
    return a +b
};

特殊：json
var show = ()=>{a:12,b:5};错误
var show = ()=>({a:12,b:5});——++用括号包起来++

匿名函数的定义与执行:

定义:
(function (){
    alert(1);
});
 
执行:
1.
(function (){
    alert(1);
})();
2.
(function (){
    alert(11);
}());
 
3.
!function(){
    alert(1);
}();
4.
~function(){
    alert(1);
 }();
5.
-function(){
    alert(1);
 }();
6.
+function(){
    alert(1);
 }();

箭头函数注意事项.特性:

一、干掉了arguments 用...args解决

exp:

<script>
//箭头函数里面没有arguments
    
function sum1(){
    //argument
    console.log(arguments);
}
console.log(sum1(1,2,3,4,5));
var sum2 = ()=>{
    console.log(arguments);
}
console.log(sum2(1,2,3,4,5));

</script>

res:

解决方法:
解构赋值

<script>
//箭头函数里面没有arguments
var sum = (...args)=>{
    console.log(args);
}
sum(1,2,3,4,5);

</script>

res:

二、不能用箭头函数建立类 用class解决

res:

三、this 指向父级

<script>
function Person(){
 
 alert(this);  
} 
var p1 = Person();//this:Window

var p2 = new Person();//this:Object

document.onclick = Person;//this:HTMLDocument
</script>

---

==路由==：

https://reacttraining.com/react-router/

https://github.com/ReactTraining/react-router

http://react-china.org/t/react-router4/15843

Vue路由：

一、安装

cnpm i -S vue-router

二、引入

import VueRouter from "vue-router"

三、注册成为vue插件

Vue.use(VueRouter);

四、建立路由对象

let router = new VueRouter({
    routes:[
        {path,name,componet,componets,children}
    ]
});

五、注入到vue实例中

new Vue({router});

六、页面上使用路由：展示、跳转

跳转:

<router-link :to={path,query|name:params}>

展示:

react路由

一、安装
npm i -S react-router-dom

二、引入
imoprt ReactRouter from "react-router-dom";

>三、直接使用：包含建立路由的过程

对比：

react	vue
Home	Home
	{path:"/",name:"home",componet:Home}
exact 控制匹配到/路径时不会再继续向下匹配，
path 标识路由的路径，
component 表示路径对应显示的组件。
HashRouter和BrowserRouter 是标签(使用方式：包的内容只能有一个子节点)	mode:"hash/history"
虚拟路径：basename="/basename"	虚拟路径：base:"/base"

Switch经常会用来包裹Route/Redirect，它里面不能放其余元素，用来只显示一个路由

react                                               vue

<Link to="/">Home</Link>                         <router-link to="/">Home</router-link>
<Route exact path="/" component={Home} />     {path:"/",name:"home",componet:Home}
exact      控制匹配到/路径时不会再继续向下匹配，
path       标识路由的路径，
component  表示路径对应显示的组件。

HashRouter和BrowserRouter 是标签                   mode:"hash/history"

****使用方式：包的内容只能有一个子节点

虚拟路径：

      basename="/basename"                        base:"/base"

Switch经常会用来包裹Route/Redirect，它里面不能放其余元素，用来只显示一个路由。

exp1:
Link,Route

import React, { Component } from 'react';
import {Route,Link,Switch,Redirect} from "react-router-dom";
//import {HashRouter as Router,Route,Link,Switch,Redirect} from "react-router-dom";
const Home = ()=> <div>首页</div>
const News = ()=> <div>新闻</div>
const Users = ()=> <div>用户</div>
class App extends Component {
  render() {
    return (
      <div className="App">
        <a href="/home">首页</a>
        <a href="/news">新闻</a>
        <a href="/users">用户</a>
        <hr />
        <Link to="/home">首页</Link>
        <Link to="/news">新闻</Link>
        <Link to="/users">用户</Link>
        <hr />
        <Switch>
        <Route exact path="/" component={Home}/>
        <Route path="/home" component={Home}/> 
        <Route path="/news" component={News}/>
        <Route path="/users" component={Users}/>
        {/* <Route component={Home} />
        */}
        {/*<Route path="/*" component={News}/> */}
        <Redirect to="/" />
        </Switch>
      </div>
      
    );
  }
}
export default App;

exp2:
props.location:

{   
    hash:"",    
    key:"579ijl",   
    pathname:"/news",   
    search:"?id=111",       
    state:undefined     
}

mport React, { Component } from 'react';
import {BrowserRouter as Router,Route,Link,Switch,Redirect} from "react-router-dom";
const Home = (props)=> {
  console.log("Home:",props);
  return <div>首页</div>;
};
const News = (props)=> {
  console.log("news:",props);
  return <div>新闻</div>;
};
const Users = (props)=> {
  console.log("Users:",props);
  return <div>用户</div>;
};
const refCallback = node => {
  // `node` refers to the mounted DOM element or null when unmounted
  console.log("node",node);
  return <div>用户函数</div>;
}

class App extends Component {
  render() {
    return (<Router>
      <div className="App">
        <Link to="/home">首页</Link>
        <Link to="/news?id=111">新闻</Link>
        <Link to={{       
            hash:"",
            pathname:"/users",
            search:"?username=aaa&password=123",
            state:{ fromDashboard: true },
          }}>用户</Link>
          <Link to="/refCallback" innerRef={refCallback} >用户函数</Link> 

        <hr />
        <Switch>
        <Route exact path="/" component={Home}/>
        <Route path="/home" component={Home}/> 
        <Route path="/news" component={News}/>
        <Route path="/users" component={Users}/>
        <Route path="/refCallback" component={refCallback}/>
        <Redirect to="/"/>
        </Switch>
      </div>
      </Router>
      
    );
  }
}
export default App;

exp3:

const Users = ({match})=>{
  console.log("Users:",match);
  return <div>用户-----{match.params.id}</div>
}
class App extends Component{
  render(){
    return (
      <div className = "App">
        <Link to="/users/111">用户111</Link>
        <Link to="/users/222">用户222</Link>
        <Link to="/users/333">用户333</Link>
        <hr/>
        <Switch>
          <Route path="/users/:id" component={Users}/>
        </Switch>

      </div>
    )
  }
}

res:

exp4:

import React, { Component } from 'react';
import {Route,Link,NavLink,Switch,Redirect} from "react-router-dom";

const Home = ()=> <div>首页</div>
const News = ()=> <div>新闻</div>
const Users = ()=> <div>用户</div>

class App extends Component {
  render() {
    return (
      <div className="App">
        <Link to="/home">首页</Link>
        <Link to="/news">新闻</Link>
        <Link to="/users">用户</Link>
        <hr />
        <NavLink activeClassName="selected" to="/home">首页</NavLink>  {/*点击添加class和属性*/}
        <NavLink activeClassName="selected" to="/news">新闻</NavLink>  
        <NavLink to="/users" activeStyle={{
          fontWeight: 'bold',
          color: 'red'
        }}>用户</NavLink>  

        <hr />
        <Switch>
        <Route exact path="/" component={Home}/>
        <Route path="/home" component={Home}/> 
        <Route path="/news" component={News}/>
        <Route path="/users" component={Users}/>
        <Redirect to="/"/>
        </Switch>
      </div>
      
    );
  }
}
export default App;

res:

路由传参：

一、?         

二、params     
  props.match.params.xxx
  props.match.path  -->"/users/:id" ----> route
  props.match.url   -->"/users/111" ----> link
exp5:

import React, { Component } from 'react';
import { Route,NavLink,Switch,Redirect} from "react-router-dom";
import "./index.css";

const Home = () =><div>首页</div>
const News = () =><div>新闻</div>
const Users = ({match}) =>{
  console.log(111,match)
return (<div>
  <NavLink to={`${match.url}/111`} >用户111</NavLink>
  <NavLink to={`${match.url}/222`} >用户222</NavLink>
  <NavLink to={`${match.url}/333`} >用户333</NavLink> 

  <Route path={`${match.url}/:id`} component={USerDetail}/>
  </div>)
}
const USerDetail = ({match}) =>{
  return (
    <div>
      <NavLink to={`${match.url}/info`}>用户信息</NavLink>
      <NavLink to={`${match.url}/pass`}>用户密码</NavLink>
      <Route path={`${match.path}/info`} component={UserInfo} /> 
      <Route path={`${match.path}/pass`}  component={UserPass} />      
    </div>
  )
}
const UserInfo = ({match}) => {
  return (
    <div>
      UserInfo --- {match.url}
    </div>
  );
}
const UserPass = ({match}) => {
  return (
    <div>
      UserPass --- {match.url}
    </div>
  );
}
class App extends Component{
  render(){
    return (
      <div className = "App">
        <NavLink to="/home">首页</NavLink>
        <NavLink to="/news">新闻</NavLink>
        <NavLink to="/users">用户</NavLink>
        <hr/>

        <Switch>
          <Route exact path="/" component={Home}/>
          <Route path="/home" component={Home}/>
          <Route path="/news" component={News}/>
          <Route path="/users" component={Users}/>
          <Redirect to = "/" />
        </Switch>

      </div>
    )
  }
}

export default App;

res:

获取数据： 都是从组件的属性上去获取 props

props:组成{history,location,match}

history: {go,goBack,goForward} 作跳转用

location：{hash,pathname,search,stat}

match:{params,path,url}

exp6:

import React, { Component } from 'react';
import { BrowserRouter as Router,Route,Link,Switch,withRouter} from "react-router-dom";

function Home(){
  return <div>首页</div>
}
function News(){
  return <div>新闻</div>
}
function Users(){
  return <div>用户</div>
}


class App extends Component {
 
 back(){
    //window.history.back();
    //window.history.go(-1);
    console.log(this.props);
    this.props.history.go(-1);
 }
 forward(){
    //window.history.forward();
    //window.history.go(1);
    this.props.history.go(1);
 }
 push(){
   // window.location = "/"
   this.props.history.push("/");
 }


  render() {
    return ( <Router>
        <div className="App">
            <input onClick={()=> this.back()} type="button" value="back" />
            <input onClick={()=> this.forward()} type="button" value="forward" />
            <input onClick={()=> this.push()} type="button" value="回到首页" />
            <hr />
            <Link to="/home">首页</Link>  
            <Link to="/news">新闻</Link>  
            <Link to="/users">用户</Link>  

            <hr />
            <Switch>
              <Route exact path="/" component={Home} /> 
              <Route path="/home" component={Home} /> 
              <Route path="/news" component={News} /> 
              <Route path="/users" component={Users} /> 
              <Route path="/*" component={News} /> 
            </Switch>

        </div>
      </Router>
    );
  }
}
export default withRouter(App);

res:

-----------------------------------------------------------------

withRouter: 功能 为组件添加路由信息{history,location,match}---> this.props

运行条件： 必须在 Router下面 不能在Router外面！

---

** exact Switch

---

https://reacttraining.com/react-router/core/api/Router

1.

什么叫 hash 地址，hash 地址就是指 # 号后面的 url。

假若有一个 Link 标签，点击后跳转到 /abc/def。

BrowserRouter： http://localhost:8080/abc/def
HashRouter： http://localhost:8080/#/abc/def

若是有服务器端的动态支持，建议使用 BrowserRouter，不然建议使用 HashRouter。

缘由在于，若是是单纯的静态文件，假如路径从 / 切换到 /a 后，此时刷新页面，页面将没法正常访问。

2.

将“URL”的历史记录保存在内存中（不读取或写入地址栏）的 <路由器> 。在测试和非浏览器环境（如React Native）中颇有用

3.

一个从不改变位置的 。

当用户实际上没有点击时，这在服务器端渲染场景中颇有用，所以该位置从未实际改变。所以，名称：static。当您只需插入一个位置并在渲染输出上做出断言时，它也可用于简单的测试。

如下是一个示例节点服务器，为 发送302状态代码，并为其余请求发送常规HTML

4.

一个 。

import { NativeRouter } from 'react-router-native'

<NativeRouter>
  <App/>
</NativeRouter>