How do I get the amount of custom token transfered in a transaction with @solana/web3.js?

I want to get the number of custom token that's transfered using trasnsaction signature with @solana/web3.js. How may I do that?

Thank you in advance.

Here the Javascript code to get the amount of transfered tokens using solana web3.js

var tes;
var triesGetTrans = 0;
while (!tes && triesGetTrans < 30) {
    try {
        if (triesGetTrans != 0) await sleep(10000)
        triesGetTrans++
        tes = await connection.getTransaction(updatedAccountInfo.signature, { maxSupportedTransactionVersion: 2 });
    } catch (e) {
        //console.log('Err getTransaction', updatedAccountInfo.signature);
    }
}
var consumed = 0;
if (tes && tes.meta && tes.meta.preTokenBalances && tes.meta.preTokenBalances.length > 0 ) {
    consumed = tes.meta.preTokenBalances[0].uiTokenAmount.uiAmount - tes.meta.postTokenBalances[0].uiTokenAmount.uiAmount;
}