Using a Custom Transport with MetaMask

[mario-christopher]

Hi I am trying to use Viem to read a contract.
I am using a custom transport with the Provider (window.ethereum) from Metamask, but unable to get my code to work.
Here is my code sample and the error.

      const publicClient = createPublicClient({
        chain: mainnet,
        transport: custom((window as any).ethereum),
      });

      const blockNumber = await publicClient.getBlockNumber()
      console.log('BLOCKNUMBER', blockNumber);

      const contract = getContract({
        address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
        abi: wagmiAbi,
        publicClient,
      });

     /// This call fails with the error: Error#1: JSON-RPC responses must be JSON serializable objects.
      const totalSupply = await publicClient.readContract({      
        ...contract,
        functionName: 'totalSupply',
      });
      console.log('TOTALSUPPLY', totalSupply);

Is this the correct usage with a custom Transport object ?
Thanks.

[mario-christopher]

I also tried the above with createWalletClient( ... ).extend(publicActions) and faced the same issue.

[jxom]

works for me: https://stackblitz.com/edit/viem-getting-started-qtccnn?file=index.ts

[jxom]

(please fork and repro your issue)

[mario-christopher]

Hi @jxom
Yes, the code for client.getBlockNumber() works.
But if you see my code sample, the error occurs when interacting with a Contract using the await publicClient.readContract() method.

Can you please try a code sample to interact with a Contract using window.ethereum.

Thanks.

[jxom]

Can you fork my repro and reproduce it? Thanks