How to get the balance for tokens in web3js v2?

Question

In web3js@1 we could use connection.getTokenAccountsByOwner() to get the balance details for tokens in a wallet.

In web3js@2 we have getTokenAccountsByOwner function in the rpc object, but I'm failing to use it, and there seems to be no examples anywhere. I've tried:

await rpc.getTokenAccountsByOwner(wallet.address, {
    programId: TOKEN_PROGRAM_ID,
}).send()

with TOKEN_PROGRAM_ID = address('TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA'), but I'm receiving this error:

SolanaError: JSON-RPC error: The JSON sent is not a valid `Request` object (Encoded binary (base 58) data should be less than 128 bytes, please use Base64 encoding.)

So, does anyone have a working example of getting a token balance of a wallet in web3js v2?

Answer 1

Assuming you know the mint addresses for the desired tokens, you can use findAssociatedTokenPda and pass the result to getTokenAccountBalance to get the balance.

Here's an example:

import { findAssociatedTokenPda, TOKEN_PROGRAM_ADDRESS } from '@solana-program/token';

const COINS_MINT: Record<string, Address> = {
    "USDC": address("EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v"),
}


async function getBalances(wallet: KeyPairSigner): Promise<Record<string, number>> {
    const balance = await (rpc.getBalance(wallet.address)).send();
    var output = {} as Record<string, number>;
    output['SOL'] = Number(balance.value) / Math.pow(10, 9);

    for (const token of Object.keys(COINS_MINT)) {
        if (token === 'SOL') continue;
        const [tokenAccount] = await findAssociatedTokenPda({
            mint: COINS_MINT[token],
            owner: wallet.address,
            tokenProgram: TOKEN_PROGRAM_ADDRESS,
        });
        try {
            const { value: { amount, decimals } } = await rpc
                .getTokenAccountBalance(tokenAccount)
                .send();
            output[token] = Number(amount) / Math.pow(10, decimals);
        }
        catch { } // if wallet doesn't have a balance of this token, it'll return an exception.
    }

    return output;
}

There probably is a way to retrieve all tokens as well (like we did on v1) using getTokenAccountsByOwner, but I couldn't figure it out yet.