gistfile1.txt

// Decode LogNote
// https://github.com/makerdao/dss/blob/6fa55812a5fcfcfa325ad4d9a4d0ca4033c38cab/src/lib.sol
// ethers@4

const logNoteAbi = [
{
	inputs: [
		{ indexed: true, name: 'sig', type: 'bytes4' },
		{ indexed: true, name: 'usr', type: 'address' },
		{ indexed: true, name: 'arg1', type: 'bytes32' },
		{ indexed: true, name: 'arg2', type: 'bytes32' },
		{ indexed: false, name: 'data', type: 'bytes' }
	],
	name: 'LogNote',
	type: 'event',
	},
];

const logNoteIface = new ethers.utils.Interface(logNoteAbi);

function parseLogNote(topics, data){
  try {
    return logNoteIface.parseLog({
      data: data,
      topics: [logNoteIface.events.LogNote.topic, ...topics],
    });
   } catch (e) {
	 console.log(e)
    return;
  }
}
  
// Put all topics 
// from https://etherscan.io/address/<contract_address>#events
let topics = [
"0x65fae35e000000000000000000000000...",
"0x000000000000000000000000...", 
"0x00000000000000000000000009...",
"0x0000000000000000000000000000000000..."
]

// Copy all 9 lines HEX data  
// from https://etherscan.io/address/<contract_address>#events
let data = "0x0000000000000000000....3804d9382a48db0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"

let resParseDsNote = parseLogNote(topics, data)
console.log("resParseDsNote: ", resParseDsNote)

/* Response: 
 _LogDescription {
  decode: [Function],
  name: 'LogNote',
  signature: 'LogNote(bytes4,address,bytes32,bytes32,bytes)',
  topic: '0xd3d8bec38a...',
  values: Result {
    '0': '0x65f..',
    '1': '0xabcdedf....',
    '2': '0x000000....',
    '3': '0x0000000000....',
    '4': '0x65fa....',
    sig: '0x65f....',
    usr: '0xabcd...',
    arg1: '0x000000000....',
    arg2: '0x000000000000000....',
    data: '0x65f....',
    length: 5
  }
}
*/