Decode Pump.fun trades with Yellowstone gRPC

import { readFileSync } from "node:fs";
import { BorshCoder, EventParser, type Idl } from "@coral-xyz/anchor";
import { PublicKey } from "@solana/web3.js";
import bs58 from "bs58";
import { subscribe } from "./stream.mts";

const idl = JSON.parse(readFileSync("pump.json", "utf8")) as Idl;
const parser = new EventParser(new PublicKey(idl.address), new BorshCoder(idl));

for await (const update of subscribe({
  transactions: {
    pump: {
      vote: false, failed: false,
      accountInclude: [idl.address], accountExclude: [], accountRequired: [],
    },
  },
})) {
  const transaction = update.transaction?.transaction;
  if (!transaction || transaction.meta?.err) continue;
  try {
    let eventIndex = 0;
    for (const event of parser.parseLogs(transaction.meta?.logMessages ?? [])) {
      const index = eventIndex++;
      if (event.name !== "TradeEvent") continue;
      console.log({
        signature: bs58.encode(transaction.signature),
        slot: update.transaction!.slot,
        eventIndex: index,
        side: event.data.is_buy ? "buy" : "sell",
        mint: event.data.mint.toString(),
        trader: event.data.user.toString(),
        tokenAmountRaw: event.data.token_amount.toString(),
        quoteMint: event.data.quote_mint.toString(),
        quoteAmountRaw: event.data.quote_amount.toString(),
      });
    }
  } catch (error) {
    console.error("Trade event decode failed; check IDL compatibility", error);
  }
}