Plugin Anatomy

Every plugin follows this structure:

packages/hardhat-arb-node/
├── src/
│   ├── index.ts              # Stable entrypoint (re-exports plugin)
│   └── plugin/
│       ├── index.ts          # Plugin definition
│       ├── type-extensions.ts
│       ├── tasks/            # CLI commands
│       └── hooks/            # Lifecycle hooks
└── test/

---

plugin/index.ts

The plugin entry point. Declares everything the plugin provides:

const hardhatArbNodePlugin: HardhatPlugin = {
  id: 'hardhat-arb-node',
  npmPackage: '@cobuilders/hardhat-arb-node',
  hookHandlers: {
    config: () => import('./hooks/config.js'),
    network: () => import('./hooks/network.js'),
  },
  tasks: [
    task(['arb:node', 'start'], 'Start the node')
      .setAction(() => import('./tasks/start.js'))
      .build(),
  ],
};

export default hardhatArbNodePlugin;

---

src/index.ts stays as a compatibility wrapper:

export { default } from './plugin/index.js';
export * from './plugin/index.js';

---

plugin/type-extensions.ts

Extends Hardhat's TypeScript types. This enables:

• Type checking - Invalid config options cause compile errors
• Autocomplete - IDEs suggest valid options

declare module 'hardhat/types/config' {
  interface StylusUserConfig {
    node?: ArbNodeUserConfig;
  }

  interface StylusConfig {
    node: ArbNodeConfig;
  }

  interface HardhatUserConfig {
    stylus?: StylusUserConfig;
  }

  interface HardhatConfig {
    stylus: StylusConfig;
  }
}

Now hardhat.config.ts is fully typed:

export default {
  stylus: {
    node: {
      httpPort: 8547, // ✓ Valid
      invalidOption: true, // ✗ TypeScript error
    },
  },
};

---

plugin/tasks/

Each file exports a task action. See Tasks for details.

---

plugin/hooks/

Each file exports hook functions. See Hooks for details.