EIP-1193 Error 4902: Unrecognized Chain ID Network Switch Fix

// Robust Pattern: Switch Chain with Fallback to Add Chain (Error 4902)
async function switchNetwork(provider: any, chainConfig: any) {
  try {
    await provider.request({
      method: 'wallet_switchEthereumChain',
      params: [{ chainId: chainConfig.chainIdHex }]
    });
  } catch (error: any) {
    // 4902 indicates chain has not been added to MetaMask yet
    if (error.code === 4902 || error?.data?.originalError?.code === 4902) {
      await provider.request({
        method: 'wallet_addEthereumChain',
        params: [chainConfig]
      });
    } else {
      throw error;
    }
  }
}