Deploy with low gas cost

.env

WS_URL=wss://eth-mainnet.alchemyapi.io/v2/<key>

deploy.ts

import { execSync } from "child_process";
import { BigNumber, ethers } from "ethers";
import { formatUnits } from "ethers/lib/utils";
import { exit } from "process";
require("dotenv").config();

// eth rpc web socket url
const WS_URL = process.env.WS_URL!;

const gwei = (val: string | number) => {
  return ethers.utils.parseUnits(`${val}`, "gwei");
};

const deploy = () => {
  // ... deployment code
  exit(0);
}

const main = async () => {
  execSync("forge build --force --optimize");

  const wsProvider = new ethers.providers.WebSocketProvider(WS_URL);

  const target = gwei("28");
  let done = false;
  // subscribe to every new head and check the baseFeePerGas
  wsProvider._subscribe("block", ["newHeads"], (result: any) => {
    if (done) {
      return;
    }

    const baseFeePerGas = BigNumber.from(result.baseFeePerGas);
    const humanReadableBaseFeePerGas = formatUnits(
      baseFeePerGas.toString(),
      "gwei"
    );

    if (baseFeePerGas.lte(target)) {
      console.log(humanReadableBaseFeePerGas, "✅");
      done = true;
      deploy();
    } else {
      console.log(humanReadableBaseFeePerGas, "❌");
    }
  });
};

main();

package.json

{
  "scripts": {
    "deploy": "ts-node scripts/deploy.ts"
  },
  "devDependencies": {
    "@types/node": "^17.0.24",
    "ts-node": "^10.7.0",
    "typescript": "^4.6.3"
  },
  "dependencies": {
    "dotenv": "^16.0.0",
    "ethers": "^5.6.1"
  }
}