derive offer off any offer that partially / fully consumed a transaction

deriveOffer.js

const deriveOffer = async (tx, address) => {
    let hash = tx.hash || tx.transaction.hash
    let taker = tx.Account || tx.transaction.Account

    for(let affected of (tx.meta || tx.metaData).AffectedNodes){
        let node = affected.ModifiedNode || affected.DeletedNode || affected.CreatedNode

        if(!node || node.LedgerEntryType !== 'Offer')
            continue

        if(node.NewFields)
            return hash

        if(!node.PreviousTxnID && !node.FinalFields.PreviousTxnID)
            continue
        let maker = node.FinalFields.Account

        if(maker !== address && taker !== address) 
            continue

        let previousTxnID = (!node.PreviousTxnID) ? node.FinalFields.PreviousTxnID : node.PreviousTxnID
        
        let request = {
            "id": 1,
            "command": "tx",
            "transaction": previousTxnID,
            "binary": false
        }
        let ledger_result = await client.send(request)
        return deriveOffer(ledger_result, address)
    }
}