Get any wallet tokens for a given contract using events

getERC20WalletBalance.js

function getERC20Contract(address) {
	return new ethers.Contract(address, [{
		anonymous: false,
		inputs: [
			{ indexed: true, internalType: 'address', name: 'from', type: 'address' },
			{ indexed: true, internalType: 'address', name: 'to', type: 'address' },
			{ indexed: false, internalType: 'uint256', name: 'amount', type: 'uint256' },
		],
		name: 'Transfer',
		type: 'event',
	}], signerOrProvider);
}

async function query(contract, filter, fromBlock, toBlock) {
	console.log('querying...', fromBlock, '...', toBlock);
	try {
		return await contract.queryFilter(filter, fromBlock, toBlock);
	} catch (e) {
		const step = ~~((toBlock - fromBlock) / 2);
		const middle = fromBlock + step;
		return [
			...(await query(contract, filter, fromBlock, middle)),
			...(await query(contract, filter, middle + 1, toBlock)),
		];
	}
}

export async function snapshot(erc20Address = '0x4d224452801aced8b2f0aebe155379bb5d594381', address = '0xdbfd76af2157dc15ee4e57f3f942bb45ba84af24') {
	const contract = getERC20Contract(nftAddress);
	
        // you can also decide to get all Transfer events without filter, and then be able to recompose 
	// all wallets!
	const transferToFilter = contract.filters.Transfer(undefined, address);
	const transferFromFilter = contract.filters.Transfer(address);

	const logs = [
		...(await query(contract, transferToFilter, undefined, undefined)),
		...(await query(contract, transferFromFilter, undefined, undefined)),
	];

	logs.sort((a, b) => {
		if (a.blockNumber !== b.blockNumber) {
			return a.blockNumber - b.blockNumber;
		}

		return a.logIndex - b.logIndex;
	});

	let balance = 0;

	logs.forEach((log) => {
		const args = log.args;
		const amount = args[2].toNumber();
		if (args[1].toLowerCase() == address) {
      balance += amount;
		} else if (args[0].toLowerCase() == address) {
      balance -= amount;
		}
	});

	return balance;
}

getERC721WalletTokens.js

function getNFTContract(address) {
	return new ethers.Contract(address, [{
		anonymous: false,
		inputs: [
			{ indexed: true, internalType: 'address', name: 'from', type: 'address' },
			{ indexed: true, internalType: 'address', name: 'to', type: 'address' },
			{ indexed: true, internalType: 'uint256', name: 'tokenId', type: 'uint256' },
		],
		name: 'Transfer',
		type: 'event',
	}], signerOrProvider);
}

async function query(contract, filter, fromBlock, toBlock) {
	console.log('querying...', fromBlock, '...', toBlock);
	try {
		return await contract.queryFilter(filter, fromBlock, toBlock);
	} catch (e) {
		const step = ~~((toBlock - fromBlock) / 2);
		const middle = fromBlock + step;
		return [
			...(await query(contract, filter, fromBlock, middle)),
			...(await query(contract, filter, middle + 1, toBlock)),
		];
	}
}

export async function snapshot(nftAddress = '0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d', address = '0xdbfd76af2157dc15ee4e57f3f942bb45ba84af24') {
	const contract = getNFTContract(nftAddress);

	const transferToFilter = contract.filters.Transfer(undefined, address);
	const transferFromFilter = contract.filters.Transfer(address);

	const logs = [
		...(await query(contract, transferToFilter, undefined, undefined)),
		...(await query(contract, transferFromFilter, undefined, undefined)),
	];

	logs.sort((a, b) => {
		if (a.blockNumber !== b.blockNumber) {
			return a.blockNumber - b.blockNumber;
		}

		return a.logIndex - b.logIndex;
	});

	const holdings = [];

	logs.forEach((log) => {
		const args = log.args;
		const id = args[2].toNumber();
		if (args[1].toLowerCase() == address) {
			holdings.push(id);
		} else if (args[0].toLowerCase() == address) {
			holdings.splice(holdings.indexOf(id), 1);
		}
	});

	return holdings;
}