js fetch 实现 ping效果

实际业务终于到的，在部分环境中可能存在网络不稳定的因素，wms手持有时候联网了但实际访问不到网页，很是尴尬
网上找到的大多数方案是通过image去实现的，我也曾参照过，但似乎效果不好
于是利用fetch写了个

import React, { Component } from 'react'
import { View,TextInput,ScrollView,Text } from 'react-native'
import { List, Button,Flex } from 'antd-mobile'

const Item = List.Item
class PingTest extends Component {
  constructor(props) {
    super(props)
    // 初始状态
    this.state = {
      ping:'',
      msglist:[],
    }
    this.cycle = null
  }

  pingCycle = () => {
    const { ping,msglist } = this.state
    const start = (new Date()).getTime()
    fetch(`http://${ping}`).then(() => {
      const delta = (new Date()).getTime() - start
      if (delta > 5000) {
        msglist.push({
          status: 0,
          msg: `ping ${ping} 连接超时`,
        })
      } else {
        msglist.push({
          status: 1,
          msg: `ping ${ping} time=${delta} ms`,
        })
      }

      this.setState({
        msglist,
      })
    }).catch((err) => {
      msglist.push({
        status: 0,
        msg: `ping ${ping} 连接失败`,
      })
      this.setState({
        msglist,
      })
    })
  }

  handlePing = () => {
    this.cycle = setInterval(this.pingCycle,1000)
  }
  handleStopPing = () => {
    clearInterval(this.cycle)
  }


  render() {
    const {msglist} = this.state
    return (
      <View style={{ height: '100%'}}>
          <List>
              <Item>
                <TextInput
                  onChangeText={text => this.setState({ping: text})}
                />
              </Item>
              <Item>
                <Flex>
                  <Flex.Item flex={1}><Button type="primary" onClick={this.handlePing.bind(this)}>Ping</Button></Flex.Item>
                  <Flex.Item flex={1}><Button onClick={this.handleStopPing.bind(this)}>停止</Button></Flex.Item>
                </Flex>


              </Item>
          </List>
          <ScrollView style={{ height: 200,backgroundColor:"#000"}}>
            {msglist.length ? msglist.map(e =>
              <Flex>
                <Flex.Item>
                  <Text style={{color: e.status === 1 ? '#87d068' : '#f50'}}>{e.msg}</Text>
                </Flex.Item>
              </Flex>):null}
          </ScrollView>
      </View>
    )
  }
}

export default PingTest