Swap (Uniswap V2) event signature and topic0

import { createPublicClient, http, parseAbiItem } from "viem"
import { mainnet } from "viem/chains"

const client = createPublicClient({ chain: mainnet, transport: http() })

const logs = await client.getLogs({
  address: "0xb4e16d0168e52d35cacd2c6185b44281ec28c9dc",
  event: parseAbiItem("event Swap(address indexed sender, uint256 amount0In, uint256 amount1In, uint256 amount0Out, uint256 amount1Out, address indexed to)"),
  fromBlock: "latest",
})

for (const log of logs) console.log(log.args) // { sender, amount0In, amount1In, amount0Out, amount1Out, to }

import { Interface, JsonRpcProvider } from "ethers"

const provider = new JsonRpcProvider(process.env.RPC_URL)
const iface = new Interface(["event Swap(address indexed sender, uint256 amount0In, uint256 amount1In, uint256 amount0Out, uint256 amount1Out, address indexed to)"])

const logs = await provider.getLogs({
  address: "0xb4e16d0168e52d35cacd2c6185b44281ec28c9dc",
  topics: [iface.getEvent("Swap")!.topicHash],
})

for (const log of logs) console.log(iface.parseLog(log)?.args)

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_getLogs",
  "params": [
    {
      "address": "0xb4e16d0168e52d35cacd2c6185b44281ec28c9dc",
      "topics": [
        "0xd78ad95fa46c994b6551d0da85fc275fe613ce37657fb8d5e3d130840159d822"
      ],
      "fromBlock": "latest"
    }
  ]
}

event Swap(address indexed sender, uint256 amount0In, uint256 amount1In, uint256 amount0Out, uint256 amount1Out, address indexed to);

// inside a function:
emit Swap(sender, amount0In, amount1In, amount0Out, amount1Out, to);