I'm playing around with web3 and frontend trying to read something off the ethereum blockchain. What i wanted to do is to verify the owner of a NFT (erc721).
I've used this piece of code here that enable me to check the balanceOf a certain ERC20 linked to the connected wallet address
function getERC20TokenBalance(tokenAddress, walletAddress, callback) {
let minABI = [
// balanceOf
{
"constant":true,
"inputs":[{"name":"_owner","type":"address"}],
"name":"balanceOf",
"outputs":[{"name":"balance","type":"uint256"}],
"type":"function"
},
// decimals
{
"constant":true,
"inputs":[],
"name":"decimals",
"outputs":[{"name":"","type":"uint8"}],
"type":"function"
}
];
let contract = web3.eth.contract(minABI).at(tokenAddress);
contract.balanceOf(walletAddress, (error, balance) => {
// ERC20トークンの decimals を取得
contract.decimals((error, decimals) => {
balance = balance.div(10**decimals);
console.log(balance.toString());
callback(balance);
});
});
}
setInterval(function() {
let tokenAddress = '0x50f5474724e0ee42d9a4e711ccfb275809fd6d4a';
let walletAddress = web3.eth.accounts[0];
if(tokenAddress != "" && walletAddress != "") {
getERC20TokenBalance(tokenAddress, walletAddress, (balance) => {
document.getElementById('text-bal').innerText = balance.toFixed(3);
});
};
}, 100);
now i would like to verify a certain NFT, which i used 0x50f5474724e0ee42d9a4e711ccfb275809fd6d4a (a SANDBOX land contract). With balanceOf, it does show me this address has LAND NFT in it, but i wanted to check for the tokenID, by changing it to
let contract = web3.eth.contract(minABI).at(tokenAddress);
contract.ownerOf('18429');
it returns nothing, can you guys point me to the right direction :) ?