InstaDecoder.js

const { web3 } = require("./config");
const BN = require('bignumber.js');

const ABI = [{
    "anonymous": false,
    "inputs": [
      {
        "indexed": false,
        "name": "cdpNum",
        "type": "uint256"
      },
      {
        "indexed": false,
        "name": "owner",
        "type": "address"
      }
    ],
    "name": "LogOpen",
    "type": "event"
}];

function getTopicsAndData(logArr) {
    for (let i = 0; i < logArr.length; i++) {
        if (logArr[i].address == "0x0bFf4468bD9f6046b98bbbe8479C6B939397a6E2") {
            if (web3.utils.keccak256('LogOpen(uint256,address)') == logArr[i].topics[0]) {
                var inObj = {
                    data: logArr[i].data,
                    topics: logArr[i].topics
                };
                return inObj; 
            }
        }
    }
}

async function getTransactionLogs(txHash) {
    try {
        return await web3.eth.getTransactionReceipt(txHash);
    } catch (err) {
        return err;
    }
}

async function decodeLogs(txHash) {
    const logArr = (await getTransactionLogs(txHash)).logs;
    const tdObj = getTopicsAndData(logArr); // Topic & Data Array
    try {
        var log = web3.eth.abi.decodeLog(ABI[0].inputs, tdObj.data, tdObj.topics);
        log.cdpNum = new BN(log.cdpNum._hex).toString();
        console.log(log);
    } catch (err) {
        console.log(err);
    }
}

decodeLogs("0x6be145dbdf14a5f493f199efa694287a705b9a825c44fde8547cd2453c4e8d04");

// get new block
// loop through txn to check for registry contract

    // save build() contract address in UserWallet db collection

    // check for UserWallet
    // check for logic proxy address - LogExecute()
    // check for the internal events via logicProxy as per the logic proxy address (kyber, maker etc)
    // match them with ABI and all events encoded
    // save in decoded logs in db