Add defineConfig in hardhat/config

[alcuadrado]

This is an idea that @fvictorio had, based on eslint, but also used by astro.

Instead of letting the user do:

import type { HardhatUserConfig } from "hardhat/config";

const config: HardhatUserConfig = {};

export default config;

we can have a defineConfig function so it's just:

import { defineConfig } from "hardhat/config";

export default defineConfig({});

which is shorter, type-safe, and has autocomplete on javascript too (!)

Note: we can't use defineConfig in our own tests, because we use --isolatedDeclarations. I added a comment about it to the tsdoc of the function.

Documentation update: NomicFoundation/hardhat-website#125

[changeset-bot]

🦋 Changeset detected

Latest commit: 7774d44

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 19 packages

Name	Type
hardhat	Patch
@nomicfoundation/hardhat-ethers-chai-matchers	Patch
@nomicfoundation/hardhat-toolbox-mocha-ethers	Patch
@nomicfoundation/hardhat-node-test-runner	Patch
@nomicfoundation/hardhat-ignition-ethers	Patch
@nomicfoundation/hardhat-network-helpers	Patch
@nomicfoundation/hardhat-viem-assertions	Patch
@nomicfoundation/hardhat-ignition-viem	Patch
@nomicfoundation/hardhat-toolbox-viem	Patch
@nomicfoundation/hardhat-typechain	Patch
@nomicfoundation/hardhat-ignition	Patch
@nomicfoundation/hardhat-keystore	Patch
@nomicfoundation/hardhat-ethers	Patch
@nomicfoundation/hardhat-ledger	Patch
@nomicfoundation/hardhat-verify	Patch
@nomicfoundation/hardhat-mocha	Patch
@nomicfoundation/hardhat-viem	Patch
@nomicfoundation/ignition-core	Patch
@nomicfoundation/ignition-ui	Patch

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[Copilot]

Pull Request Overview

This PR introduces a defineConfig helper function to the Hardhat configuration API, providing a more ergonomic way to define Hardhat configurations with better type safety and autocomplete support for both TypeScript and JavaScript users.

Key changes:

• Adds defineConfig function to hardhat/config that wraps configuration objects
• Updates template files to use the new defineConfig pattern instead of explicit type annotations
• Provides comprehensive JSDoc documentation explaining usage and limitations

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
v-next/hardhat/src/config.ts	Implements the defineConfig function with type safety and documentation
v-next/hardhat/templates/hardhat-3/02-mocha-ethers/hardhat.config.ts	Updates template to use defineConfig pattern
v-next/hardhat/templates/hardhat-3/01-node-test-runner-viem/hardhat.config.ts	Updates template to use defineConfig pattern
v-next/example-project/hardhat.config.ts	Updates example project to demonstrate defineConfig usage

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[alcuadrado]

I initially thought this wasn't going to work, as the template packages needs to point to the newest version of hardhat. But turns out that changesets also bumps the version range in the template packages :)

I added a PR to the website that needs to be merged once this is released.

Also, I updated the readmes of all the packages. I don't think this requires bumping their peerDependency on hardhat, as it's just a documentation doc. /cc @kanej

[alcuadrado]

@michalbrabec this can be re-reviewed now.

[Copilot]

Pull Request Overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated no new comments.

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[alcuadrado]

Also, after releasing this we should update the branches main and tutorial of https://github.com/NomicFoundation/hardhat3-plugin-template, but it can't be done yet.