OwnershipTransferred 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: "0x57f1887a8bf19b14fc0df6fd9b2acc9af147ea85",
  event: parseAbiItem("event OwnershipTransferred(address indexed previousOwner, address indexed newOwner)"),
  fromBlock: "latest",
})

for (const log of logs) console.log(log.args) // { previousOwner, newOwner }

import { Interface, JsonRpcProvider } from "ethers"

const provider = new JsonRpcProvider(process.env.RPC_URL)
const iface = new Interface(["event OwnershipTransferred(address indexed previousOwner, address indexed newOwner)"])

const logs = await provider.getLogs({
  address: "0x57f1887a8bf19b14fc0df6fd9b2acc9af147ea85",
  topics: [iface.getEvent("OwnershipTransferred")!.topicHash],
})

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_getLogs",
  "params": [
    {
      "address": "0x57f1887a8bf19b14fc0df6fd9b2acc9af147ea85",
      "topics": [
        "0x8be0079c531659141344cd1fd0a4f28419497f9722a3daafe3b4186f6b6457e0"
      ],
      "fromBlock": "latest"
    }
  ]
}

event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

// inside a function:
emit OwnershipTransferred(previousOwner, newOwner);