@ngeth/hardhat

@ngeth/hardhat is a collection of hardhat task that comes with :

• Contract type generation for ethers
• Script runner when local node boots up for better E2E tests
• Local Block Explorer app
• Local API endpoint to emulate common cloud services (only etherscan is supported yet)

Note: @ngeth/hardhat is built for Typescript project.

Nx support: @ngeth/hardhat is built with nx and provides schematics and builders for a better nx integration.

Install

npm install @ngeth/hardhat

Setup with Nx or Angular

Update an existing project

ng generate @ngeth/hardhat:ng-add

Note: Prefer the command above over ng add @ngeth/hardhat which might be very slow.

Create a dedicated library

ng generate @ngeth/hardhat:library contracts

Options:

• outputType: "angular" | "typescript" (default: "typescript")

Setup without Nx

Setup a hardhat project following official documentation.

Update hardhat.config.ts

import '@nomiclabs/hardhat-ethers';
import '@ngeth/hardhat'; // <-- load @ngeth/hardhat

export default {
  solidity: '0.8.11',
  paths: {
    sources: './contracts',
    tests: './tests',
    artifacts: './artifacts',
  },
  // Config for @ngeth/hardhat
  ngeth: {
    outputPath: './src',
    runs: ['scripts/deploy.ts'],
    explorer: {
      api: 3000,
      app: 3001
    },
  },
};

Run Scripts

The field runs let you run scripts before ngeth:serve. This is very handy to create an initial state for your local app development. Let's see how to deploy a contract and save its address in the outputPath directory:

scripts/deploy.ts

import * as hre from 'hardhat';
import { deploy, saveAddresses } from '@ngeth/hardhat';

async function main() {
  // Deploy contract from the artifacts by their names & constructor arguments
  const addresses = await deploy(hre, {
    BaseERC721: [],
    BaseERC20: ['SYB', 'Name'],
  });
  // Save the addresses of the contracts in the outputPath directory
  await saveAddresses(hre, addresses);
}

main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

The addresses output will be a json file with the addresses by chain. This format is useful to manage addresses for contract from different chains.

addresses.json

{
  "hardhat": {
    "BaseERC721": "0x9fE46736679d2D9a65F0992F2272dE9f3c7fa6e0",
    "BaseERC20": "0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512"
  }
}

Config

outputPath

• description: Directory, relative to hardhat.config.ts, to put generated contracts classes
• required: Yes
• type: string

runs

• description: Scripts to run on @ngeth:serve after node has started. If array of string, parallel is false
• required: No
• type: string[] | { scripts: string[], parallel: boolean }
• default: []

explorer

• description: Ports used for the block explorer API and APP.
• required: No
• type: false | { api: number, app: number }
• default: { api: 3000, app: 3001 }

withImports

• description: Generate Typescript interfaces for libraries & contract imported by the exported contracts
• required: No
• type: boolean
• default: false

Tasks / Builder

@ngeth/hardhat comes with 3 custom hardhat tasks. If you use Nx or Angular, the schematics will create builders inside your workspace that wrap these tasks:

hardhat ngeth:build (@ngeth/hardhat:build):

• compiles the contracts
• generates the contract classes

hardhat ngeth:serve (@ngeth/hardhat:serve):

• compiles the contracts.
• generates the contract classes.
• starts a node on localhost:8545, and the explorer as specified in the config
• runs scripts specified under runs.

hardhat ngeth:test (@ngeth/hardhat:test):

• compiles the contracts.
• tests with jest.

If you want to test with mocha, use the regular hardhat test task.

Troubleshoot

Invalid chainId

This is an issue with metamask and hardhat https://hardhat.org/metamask-issue.html

Invalid nonce

This is an issue with metamask not beeing able to reset the nonce to 0 when you restart the node Go to Metamask > Setting > Advanced > Reset Account