你会用JS获取你当前的网络状况吗？

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我们知道，在Web端检测网速其实很简单，只需使用一个全局对象——navigation，让我们来看看它包含了哪些信息：

useNetwork

我们可以定制一个hook，以便获取当前网页的网络状态~必须包含以下要素：

• 返回所需数据的ts类、监听网络变化的enum
• 获取网络状态
• 监听网络变化，并实时更新最新的网络状态.

第一步：所需的ts类型

描述一下NetworkState的各个参数：

• since：记录检测的时间
• oline：记录网络是否可用
• rtt：记录延迟时间
• downlink：记录下载速度
• saveData：记录用户代理是否启用了数据节省模式
• effectiveType：记录网络连接类型。

// hook返回的值
interface NetworkState {
  since?: Date;
  online?: boolean;
  rtt?: number;
  downlink?: number;
  saveData?: boolean;
  effectiveType?: string;
}

// 监听网络变化的事件名enum
enum NetworkEventType {
  ONLINE = 'online',
  OFFLINE = 'offline',
  CHANGE = 'change',
}

第二步：获取网络状态

function getConnection() {
  const nav = navigator as any;
  if (typeof nav !== 'object') return null;
  return nav.connection || nav.mozConnection || nav.webkitConnection;
}

function getConnectionProperty(): NetworkState {
  const c = getConnection();
  if (!c) return {};
  return {
    rtt: c.rtt,
    saveData: c.saveData,
    downlink: c.downlink,
    effectiveType: c.effectiveType,
  };
}

第三步：实时更新网络状态

unction useNetwork(): NetworkState {
  const [state, setState] = useState(() => {
    return {
      since: undefined,
      online: navigator?.onLine,
      ...getConnectionProperty(),
    };
  });

  useEffect(() => {
    const onOnline = () => {
      setState((prevState) => ({
        ...prevState,
        online: true,
        since: new Date(),
      }));
    };

    const onOffline = () => {
      setState((prevState) => ({
        ...prevState,
        online: false,
        since: new Date(),
      }));
    };

    const onConnectionChange = () => {
      setState((prevState) => ({
        ...prevState,
        ...getConnectionProperty(),
      }));
    };

    window.addEventListener(NetworkEventType.ONLINE, onOnline);
    window.addEventListener(NetworkEventType.OFFLINE, onOffline);

    const connection = getConnection();
    connection?.addEventListener(NetworkEventType.CHANGE, onConnectionChange);

    return () => {
      window.removeEventListener(NetworkEventType.ONLINE, onOnline);
      window.removeEventListener(NetworkEventType.OFFLINE, onOffline);
      connection?.removeEventListener(NetworkEventType.CHANGE, onConnectionChange);
    };
  }, []);

  return state;
}

完整代码

import { useEffect, useState } from 'react';

export interface NetworkState {
  since?: Date;
  online?: boolean;
  rtt?: number;
  downlink?: number;
  saveData?: boolean;
  effectiveType?: string;
}

enum NetworkEventType {
  ONLINE = 'online',
  OFFLINE = 'offline',
  CHANGE = 'change',
}

function getConnection() {
  const nav = navigator as any;
  if (typeof nav !== 'object') return null;
  return nav.connection || nav.mozConnection || nav.webkitConnection;
}

function getConnectionProperty(): NetworkState {
  const c = getConnection();
  if (!c) return {};
  return {
    rtt: c.rtt,
    saveData: c.saveData,
    downlink: c.downlink,
    effectiveType: c.effectiveType,
  };
}

function useNetwork(): NetworkState {
  const [state, setState] = useState(() => {
    return {
      since: undefined,
      online: navigator?.onLine,
      ...getConnectionProperty(),
    };
  });

  useEffect(() => {
    const onOnline = () => {
      setState((prevState) => ({
        ...prevState,
        online: true,
        since: new Date(),
      }));
    };

    const onOffline = () => {
      setState((prevState) => ({
        ...prevState,
        online: false,
        since: new Date(),
      }));
    };

    const onConnectionChange = () => {
      setState((prevState) => ({
        ...prevState,
        ...getConnectionProperty(),
      }));
    };

    window.addEventListener(NetworkEventType.ONLINE, onOnline);
    window.addEventListener(NetworkEventType.OFFLINE, onOffline);

    const connection = getConnection();
    connection?.addEventListener(NetworkEventType.CHANGE, onConnectionChange);

    return () => {
      window.removeEventListener(NetworkEventType.ONLINE, onOnline);
      window.removeEventListener(NetworkEventType.OFFLINE, onOffline);
      connection?.removeEventListener(NetworkEventType.CHANGE, onConnectionChange);
    };
  }, []);

  return state;
}

export default useNetwork;