js connects to web3, connects to the little fox metamask wallet, realizes network switching and network creation after the chain is incorrect

Directly upload the code, let me change all the configurations here to the official chain 56, once the current chain of the user’s small fox wallet is inconsistent, ask to switch the network, if not, create a network, after the network switch is successful, receive the monitoring, and reconnect web3, is to re-call some connectWeb3 methods, and then connect to the contract

  connectWeb3: async function () { 
// 判断链对不，链不对就请求切换网络，或者添加网络，
    if (window.ethereum) {
      try {
        await (window.ethereum as any).request({
          method: 'wallet_switchEthereumChain',
          params: [{
            chainId: Web3.utils.numberToHex(56) // 目标链ID
          }]
        })
      } catch (e) {
        if ((e as any).code === 4902) {
          try {
            await (window.ethereum as any).request({
                method: 'wallet_addEthereumChain',
                params: [
                  {
                    chainId: Web3.utils.numberToHex(56), // 目标链ID
                    chainName: 'Binance Smart Chain Mainnet',
                    nativeCurrency: {
                      name: 'bnb',
                      symbol: 'bnb',
                      decimals: 18
                    },
                    rpcUrls: ['https://bsc-dataseed.binance.org'], // 节点
                    blockExplorerUrls: ['https://www.bscscan.com']
                  }
                ]
              })
          } catch (ee) {
            //
          }
        } else if ((e as any).code === 4001) return
      }
    }


    // 监听账户变化
    const func: Function = async function (accounts) {
      _this.account = accounts[0];
      if (_this.isConnect) {
        console.log("Contract Account Changed");
        _this.init();// 清空数据
        _this.connectWeb3();// 链变化，然后重新调用此方法，连接web3
      }
    };
    let web3Provider: any = null;
    if (window.ethereum) {
      (window.ethereum as any).autoRefreshOnNetworkChange = false;
      (window.ethereum as any).on("accountsChanged", func);
    // 监听链id变化
      (window.ethereum as any).on("chainChanged", (chainId1) => {
        console.log("Chain Changed");
        _this.chainId = chainId1;
        func([_this.account]);
      });
      web3Provider = window.ethereum;
      try {
        await (window.ethereum as any).enable();
      } catch (error) {
        console.error("User denied account access");
      }
    } else if (window.web3) {
      web3Provider = window.web3.currentProvider;
    } else {
      web3Provider = new                 
      Web3.providers.HttpProvider(ChainLink[TargetChainId.toString()]);// 连接rpc网络
    }
    _this.web3 = new Web3(web3Provider);
    _this.web3.eth.getAccounts(function (error, result) {
      if (!error) console.log(result);
    });
    _this.isConnect = true;
    _this.account = (window.ethereum as any).selectedAddress || null;
    _this.chainId = (window.ethereum as any).networkVersion || null;
    if(_this.chainId!=TargetChainId) return;// 链不对,就不去连接合约了
    if (_this.account) {
      const time = Math.round(new Date().valueOf() / 1000);
    // 签名
      _this.web3.eth.personal.sign("Sign this message to login Game." + time, _this.account)
        .then((res) => {
          _this.signature = res + "|" + time;
        });
      _this.connectContract();// 连接合约
    }
    return _this.account;
}