Creating a custom task

Let’s now define a task that prints the myAccount address of the network Hardhat is connected to, with a customizable title.

Defining the task in your HardhatPlugin object

Tasks are defined in the tasks property of the HardhatPlugin object.

If you open packages/plugin/src/index.ts, you’ll find the tasks property, an array of task definitions. You already have one:

task("my-task", "Prints a greeting.")
  .addOption({
    name: "who",
    description: "Who is receiving the greeting.",
    type: ArgumentType.STRING,
    defaultValue: "Hardhat",
  })
  .setAction(() => import("./tasks/my-task.js"))
  .build();

Replace it with this code:

task("my-account", "Prints your account.")
  .addOption({
    name: "title",
    description: "The title to use before printing the account.",
    type: ArgumentType.STRING,
    defaultValue: "My account:",
  })
  .setAction(() => import("./tasks/my-account.js"))
  .build(),

You’ll get an error in the highlighted line because a file is missing. We’ll create it in the next section.

Creating a task action file

The task action is defined in a separate file that’s only imported when the task runs.

Create the file packages/plugin/src/tasks/my-account.ts with this code:

import { HardhatRuntimeEnvironment } from "hardhat/types/hre";

interface MyAccountTaskArguments {
  title: string;
}

export default async function (
  taskArguments: MyAccountTaskArguments,
  hre: HardhatRuntimeEnvironment,
) {
  const conn = await hre.network.connect();
  console.log(taskArguments.title);
  console.log(conn.myAccount);
}

Here we define the task arguments interface and action (the function that executes when the task runs).

The task action must be an async function and exported as default.

Tip

The task arguments interface, MyAccountTaskArguments, is type-safe. You’ll get a compilation error if it doesn’t match the arguments in the task definition.

You can remove packages/plugin/src/tasks/my-task.ts, as it’s no longer needed.

Trying out your task

To try out your task, build the plugin and run this in the example project:

pnpm hardhat my-account --title MiCuenta
MiCuenta
0x70997970c51812dc3a010c7d01b50e0d17dc79c8