text: import React from 'react'
  import PropTypes from 'prop-types'
  export default class Route extends React.Component{
      static contextTypes = {
          location:PropTypes.object
      }
      render(){
          let {path,component:Component} = this.props
          let {location} = this.context;
          if((location&&path==location.pathname) || location.pathname.startsWith(path)){
              return <Component location={location} />
          }
          return null
      }
  }
  