Web3 & DApp Development Fundamentals · Lesson

Scripts and Tasks

Automate workflows.

Scripts and Tasks is a free Web3 & DApp Development Fundamentals lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Web3 & DApp Development Fundamentals learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Scripts vs Tasks

Hardhat offers two ways to automate work:

Scripts — plain Node.js files you run for one-off jobs like deployment.
Tasks — reusable commands integrated into the Hardhat CLI with arguments and help text.

Use scripts for ad-hoc automation, tasks for repeatable commands your team reuses.

A Deployment Script

Scripts live in scripts/. A deploy script uses ethers from the Hardhat Runtime Environment:

const hre = require("hardhat");

async function main() {
  const Greeter = await hre.ethers.getContractFactory("Greeter");
  const greeter = await Greeter.deploy();
  await greeter.waitForDeployment();
  console.log("Deployed to:", await greeter.getAddress());
}

main();

const hre = require("hardhat");

async function main() {
  const Greeter = await hre.ethers.getContractFactory("Greeter");
  const greeter = await Greeter.deploy();
  await greeter.waitForDeployment();
  console.log("Deployed to:", await greeter.getAddress());
}

main();

Running a Script

Run a script through Hardhat so it injects the runtime environment and network:

npx hardhat run scripts/deploy.js

Add --network to target a specific network. Without it, the script runs against an ephemeral in-process network.

npx hardhat run scripts/deploy.js --network localhost

The Runtime Environment

The Hardhat Runtime Environment (HRE) is injected automatically and gives you:

hre.ethers — the ethers.js helpers.
hre.network — info about the active network.
hre.config — the resolved configuration.

Inside tasks the HRE is the second argument; in scripts it is the hardhat module.

Defining a Custom Task

Define tasks in hardhat.config.js using the task helper:

const { task } = require("hardhat/config");

task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
  const accounts = await hre.ethers.getSigners();
  for (const account of accounts) {
    console.log(account.address);
  }
});

const { task } = require("hardhat/config");

task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
  const accounts = await hre.ethers.getSigners();
  for (const account of accounts) {
    console.log(account.address);
  }
});

Running a Custom Task

Once defined, your task appears in the CLI like any built-in command:

npx hardhat accounts

It also shows up under npx hardhat with its description, so teammates can discover it without reading the config.

npx hardhat accounts

Task Parameters

Tasks accept named parameters with addParam:

task("balance", "Prints an account balance")
  .addParam("account", "The address")
  .setAction(async (taskArgs, hre) => {
    const bal = await hre.ethers.provider.getBalance(taskArgs.account);
    console.log(hre.ethers.formatEther(bal), "ETH");
  });

Run it with npx hardhat balance --account 0x....

task("balance", "Prints an account balance")
  .addParam("account", "The address")
  .setAction(async (taskArgs, hre) => {
    const bal = await hre.ethers.provider.getBalance(taskArgs.account);
    console.log(hre.ethers.formatEther(bal), "ETH");
  });

Overriding Built-in Tasks

You can extend existing tasks like compile using the same name. Use runSuper to call the original behavior:

task("compile", async (args, hre, runSuper) => {
  console.log("Before compiling...");
  await runSuper(args);
  console.log("Done compiling!");
});

This is handy for adding logging or post-processing steps.

task("compile", async (args, hre, runSuper) => {
  console.log("Before compiling...");
  await runSuper(args);
  console.log("Done compiling!");
});

Subtasks

Subtasks are internal tasks not shown in the main help list. They let you break complex tasks into reusable pieces:

const { subtask } = require("hardhat/config");

subtask("print-network", async (args, hre) => {
  console.log("Network:", hre.network.name);
});

Call subtasks from other tasks with hre.run("print-network").

const { subtask } = require("hardhat/config");

subtask("print-network", async (args, hre) => {
  console.log("Network:", hre.network.name);
});

When to Use Each

Rules of thumb:

Need a quick deploy or migration? Write a script.
Need a reusable command with parameters and help text? Write a task.
Need to compose internal steps? Use subtasks.

Both scripts and tasks have full access to the HRE.

Scripts in package.json

For convenience, wrap common commands as npm scripts:

{
  "scripts": {
    "deploy": "hardhat run scripts/deploy.js --network localhost",
    "test": "hardhat test"
  }
}

Then teammates run npm run deploy without memorizing flags.

{
  "scripts": {
    "deploy": "hardhat run scripts/deploy.js --network localhost",
    "test": "hardhat test"
  }
}

Quick Check

Test your understanding of scripts and tasks.

Recap

You learned how to automate Hardhat workflows.

Scripts in scripts/ run via npx hardhat run for one-off jobs.
Tasks defined with task() become first-class CLI commands.
The HRE exposes ethers, network, and config.
addParam adds CLI arguments; runSuper extends built-in tasks.
Subtasks compose internal steps callable with hre.run.

Frequently asked questions

Is the “Scripts and Tasks” lesson free?

Yes — the full text of “Scripts and Tasks” is free to read here on the web, and the Web3 & DApp Development Fundamentals course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Web3 & DApp Development Fundamentals course, upgrade to CoddyKit PRO.

What will I learn in “Scripts and Tasks”?

Automate workflows. You practise Web3 & DApp Development Fundamentals with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Web3 & DApp Development Fundamentals?

No prior experience is required. Web3 & DApp Development Fundamentals on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Scripts and Tasks” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Web3 & DApp Development Fundamentals lesson?

Yes. Every Web3 & DApp Development Fundamentals lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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