Approval 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: "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
  event: parseAbiItem("event Approval(address indexed owner, address indexed spender, uint256 value)"),
  fromBlock: "latest",
})

for (const log of logs) console.log(log.args) // { owner, spender, value }

import { Interface, JsonRpcProvider } from "ethers"

const provider = new JsonRpcProvider(process.env.RPC_URL)
const iface = new Interface(["event Approval(address indexed owner, address indexed spender, uint256 value)"])

const logs = await provider.getLogs({
  address: "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
  topics: [iface.getEvent("Approval")!.topicHash],
})

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_getLogs",
  "params": [
    {
      "address": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
      "topics": [
        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925"
      ],
      "fromBlock": "latest"
    }
  ]
}

event Approval(address indexed owner, address indexed spender, uint256 value);

// inside a function:
emit Approval(owner, spender, value);