Web3js BatchRequest Balances from List of Tokens Fails on execute() - ethereum

Question

This is my batch.js file which contains the relevant code. I am importing some variables from other files but I've isolated the problem to this file:
const Web3 = require('web3')
const fs = require('fs')
const { convertToNumber, getTokens } = require('./utils')
const { abi, bathEndpoint, walletAddress, blockNumber } = require('./constant.js')
const web3 = new Web3(new Web3.providers.HttpProvider(bathEndpoint))
const generateContractFunctionList = ({ tokens, blockNumber }) => {
const batch = new web3.BatchRequest()
tokens.map(async ({ address: tokenAddress, symbol, decimals }) => {
// console.log('tokenAddress :>> ', tokenAddress)
if (tokenAddress != null && tokenAddress != '') {
const contract = new web3.eth.Contract(abi)
contract.options.address = tokenAddress
try {
batch.add(
contract.methods
.balanceOf(walletAddress)
.call.request({}, blockNumber)
)
} catch (error) {
console.error('Error adding request to batch for token ', tokenAddress)
}
}
})
return batch
}
const main = async () => {
//const { tokens } = await getTokens()
const tokens = JSON.parse(fs.readFileSync('./tokenArrayFormatted1.json'));
console.log('tokens retrieved :>> ', tokens.length)
// const batch = generateContractFunctionList({ tokens })
// query block number
const batch = generateContractFunctionList({ tokens, blockNumber: blockNumber })
const tokenBalances = {}
const tokensIgnored = []
let batchData
try {
batchData = await batch.execute()
} catch (error) {
console.error('Error retrieving balances for some tokens')
batchData = error
}
try {
batchData.response.forEach((res, index) => {
const { name, decimals, symbol } = tokens[index]
if (res && res._hex) {
tokenBalances[name] = `${convertToNumber(res._hex, decimals)} ${symbol}`
} else {
tokensIgnored.push(name)
}
})
} catch (error) {
console.error('Error retrieving balances for some tokens')
batchData = error
}
console.log(
'The following tokens returned an error when checking balance:',
tokensIgnored
)
console.log('----------')
console.log(
`Balance checked for ${Object.keys(tokenBalances).length} tokens:`
)
console.log(tokenBalances)
}
main()
tokenArrayFormatted1.json looks like this:
[
{
"chainId": 1,
"address": "0xf3AE5d769e153Ef72b4e3591aC004E89F48107a1",
"name": "Deeper Network",
"symbol": "DPR",
"decimals": 18
},
{
"chainId": 1,
"address": "0xf680429328caaaCabee69b7A9FdB21a71419c063",
"name": "Butterfly Protocol Governance Token",
"symbol": "BFLY",
"decimals": 18
}
]
When I run node batch.js I keep getting an error telling me that batchData.response is undefined when the code tries to do a forEach over it. I logged batch to the console and it looked like this.
Batch {
requestManager: RequestManager {
provider: HttpProvider {
withCredentials: false,
timeout: 0,
headers: undefined,
agent: undefined,
connected: false,
host: 'https://USERNAME:PASSWORD#BASEURLOFGETHNODE.com',
httpsAgent: [Agent]
},
providers: {
WebsocketProvider: [Function: WebsocketProvider],
HttpProvider: [Function: HttpProvider],
IpcProvider: [Function: IpcProvider]
},
subscriptions: Map(0) {}
},
requests: [
{
params: [Array],
callback: undefined,
method: 'eth_call',
format: [Function: bound ]
},
{
params: [Array],
callback: undefined,
method: 'eth_call',
format: [Function: bound ]
}
]
}
Where USERNAME,PASSWORD, and BASEURLOFGETHNODE refer to my actual credentials.
And then batchData which is created by the line let batchData = await batch.execute() is undefined when logged to the console. So clearly await batch.execute() is producing nothing. I am using Chainstack Geth node API's (with an archive node) and web3js as indicated above. What seems to be the problem?

Answer 1

let batchData = await batch.execute()
batch.execute() does not return a promise if you read the source code, in fact it sends the JSON RPC batch request and call each request callback individually, so what you need to do is turn the execute function into asynchronous one returning an array of responses, and this is how to do it :
const Jsonrpc = require('web3-core-requestmanager/src/jsonrpc');
var { errors } = require('web3-core-helpers');
function executeAsync(batch) {
return new Promise((resolve, reject) => {
var requests = batch.requests;
batch.requestManager.sendBatch(requests, (err, results) => {
results = results || [];
var response = requests.map((request, index) => {
return results[index] || {};
}).map((result, index) => {
if (result && result.error) {
return errors.ErrorResponse(result);
}
if (!Jsonrpc.isValidResponse(result)) {
return errors.InvalidResponse(result);
}
return requests[index].format ? requests[index].format(result.result) : result.result;
});
resolve(response);
});
})
}
To use this function :
(async () => {
var batch = new web3.BatchRequest();
batch.add(web3.eth.getBlock.request("latest"));
var batchResponse = await executeAsync(batch);
console.log(batchResponse);
})()