How do I use the processFunc on FetchRequests?

[fahimuddin-brillmark]

Ethers Version

6.3.0

Search Terms

assertOk, typeError, fetchRequest, processFunc

Describe the Problem

Hello team,

I am having an issue while using JsonRpcProvider api to get the chain id from an endpoint using eth_chainId method. So, I am using .send() method which is triggering processFunc callback from FetchRequest class. In the processFunc I am getting this error.

Looks like the error is happening in here : https://github.com/ethers-io/ethers.js/blob/main/src.ts/providers/provider-jsonrpc.ts
At Line 24 - response.assertOk();

Why I am getting that error while doing simple call using .send() method.

The Reason I am doing this :
I want to catch numeric error codes from FetchResponse class instead of getting string error codes from .send() method from ErrorCode : https://docs.ethers.org/v6/api/utils/errors/#ErrorCode

Code Snippet

const fetchRequest = new FetchRequest(endpoint);
fetchRequest.processFunc = (req, resp) => {
    console.log(resp.statusCode);
    console.log(resp.bodyJson);
};

const run = async () => {
    try {
        const provider = new JsonRpcProvider(fetchRequest);
        const response = await provider.send(method, []);
        console.log("response : ", response);
    } catch (error) {
        console.log(error);
    }
}

run();

Contract ABI

No response

Errors

TypeError: Cannot read properties of undefined (reading 'assertOk')
    at JsonRpcProvider._send (file:///Users/fahimuddin/Documents/Works/Developments/Office/Brillmark/rpc-test/node_modules/ethers/lib.esm/providers/provider-jsonrpc.js:766:18)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async file:///Users/fahimuddin/Documents/Works/Developments/Office/Brillmark/rpc-test/node_modules/ethers/lib.esm/providers/provider-jsonrpc.js:235:40
JsonRpcProvider failed to startup; retry in 1s

Environment

node.js (v12 or newer)

Environment (Other)

No response

[ricmoo]

The processFunc must return a FetchResponse. Right now you are retuning undefined.

Try adding return resp to the end of your function.