Hardhat simple storage notes
Setting up Hard hat
install hardhat with
yarn add --dev hardhat
init hard hat with
Spencers-iMac:test hh setup spencershelton$ yarn hardhat
yarn run v1.22.15
warning package.json: No license field
$ '/Users/spencershelton/Documents/CodeCampSmartContract/test hh setup/node_modules/.bin/hardhat'
888 888 888 888 888
888 888 888 888 888
888 888 888 888 888
8888888888 8888b. 888d888 .d88888 88888b. 8888b. 888888
888 888 "88b 888P" d88" 888 888 "88b "88b 888
888 888 .d888888 888 888 888 888 888 .d888888 888
888 888 888 888 888 Y88b 888 888 888 888 888 Y88b.
888 888 "Y888888 888 "Y88888 888 888 "Y888888 "Y888
👷 Welcome to Hardhat v2.11.2 👷
? What do you want to do? …
❯ Create a JavaScript project
Create a TypeScript project
Create an empty hardhat.config.js
Quit
after picking project type will ask you a few set up questions:
What do you want to do? · Create a JavaScript project
✔ Hardhat project root: · /Users/spencershelton/Documents/CodeCampSmartContract/test hh setup
✔ Do you want to add a .gitignore? (Y/n) · y
✔ Do you want to install this sample project's dependencies with yarn (@nomicfoundation/hardhat-toolbox @nomicfoundation/hardhat-network-helpers @nomicfoundation/hardhat-chai-matchers @nomiclabs/hardhat-ethers @nomiclabs/hardhat-etherscan chai ethers hardhat-gas-reporter solidity-coverage @typechain/hardhat typechain @typechain/ethers-v5 @ethersproject/abi @ethersproject/providers)? (Y/n) · y
after hardhat is setup if you run yarn hardhat you will get the avialable tasks hardhat provides
yarn hardhat
yarn run v1.22.15
warning package.json: No license field
$ '/Users/spencershelton/Documents/CodeCampSmartContract/test hh setup/node_modules/.bin/hardhat'
Hardhat version 2.11.2
Usage: hardhat [GLOBAL OPTIONS] <TASK> [TASK OPTIONS]
GLOBAL OPTIONS:
--config A Hardhat config file.
--emoji Use emoji in messages.
--flamegraph Generate a flamegraph of your Hardhat tasks
--help Shows this message, or a task's help if its name is provided
--max-memory The maximum amount of memory that Hardhat can use.
--network The network to connect to.
--show-stack-traces Show stack traces (always enabled on CI servers).
--tsconfig A TypeScript config file.
--typecheck Enable TypeScript type-checking of your scripts/tests
--verbose Enables Hardhat verbose logging
--version Shows hardhat's version.
AVAILABLE TASKS:
check Check whatever you need
clean Clears the cache and deletes all artifacts
compile Compiles the entire project, building all artifacts
console Opens a hardhat console
coverage Generates a code coverage report for tests
flatten Flattens and prints contracts and their dependencies
gas-reporter:merge
help Prints this message
node Starts a JSON-RPC server on top of Hardhat Network
run Runs a user-defined script after compiling the project
test Runs mocha tests
typechain Generate Typechain typings for compiled contracts
verify Verifies contract on Etherscan
To get help for a specific task run: npx hardhat help [task]
✨ Done in 3.64s.
If youd like to add custom tasks create a task like so
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)
}
})
How to spin up a local hardhat network
yarn hardhat node
to deploy on hardhat node you have to set up a new network in you hardhat config file. you dont have to add accounts because hardhat sets that up for u
localHost: {
url: "http://127.0.0.1:8545/",
chainId: 31337,
},
then deploy your contract like so
yarn hardhat run scripts/deploy.js --network localHost
Using Console to communicate with blockchain
run console task to open up a console to manipulate blockchain directly in your terminal
yarn hardhat console --network localhost
Deploy Script notes
Deploy contract with ethers
const { ethers, run, network } = require("hardhat")
async function main() {
const SimpleStorageFactory = await ethers.getContractFactory(
"SimpleStorage"
)
console.log("Deploying contract...")
const simpleStorage = await SimpleStorageFactory.deploy()
await simpleStorage.deployed(1)
}
You can run any task directly in a deploy script by importing the run package from hard hat
const { run } = require("hardhat")
You can get info about the current network your on by importing the network package
const { network } = require("hardhat")
Then you could programically do certain things on specific networks like so
if (network.config.chainId === 4 && process.env.ETHERSCAN_API_KEY) {
console.log("Waitng for 6 blocks")
//potentially etherscan can take a bit for it to be up on website so wait some blocks
await simpleStorage.deployTransaction.wait(6)
await verify(simpleStorage.address, [])
}
Networks
So normally you need the rpc url and private key usually to deploy a smart contract so how is this working?
Hardhat comes built in with a hardhat network, a local ehtereum network node designed for development.
When ever you deploy a script it uses hardhat network by default which automatically comes with rpc and private key
We should be specific with the current default network by specifying it in hardhat.config.js
module.exports = {
defaultNetwork: "hardhat",
solidity: "0.8.9",
}
you can change network in command line by specifing network
yarn hardhat run scripts/deploy.js --network hardhat
if youd like to use a different network such as a test net like rinkeby you need to config that network in the hardhat.config.js
rinkeby: {
url: RINKEBY_RPC_URL,
accounts: [PRIVATE_KEY],
chainId: 4,
},
now that you configured your another network you can now deploy onto rinkeby
yarn hardhat run scripts/deploy.js --network rinkeby
How to verify your contract
You can use a block explorer's api to verifiy a smart contract programically.
With hardhat we can add plugins to hardhat. To make verifying the contract easier we can add hardhat-etherscan
yarn add --dev @nomiclabs/hardhat-etherscan
Next to have hardhat-etherscan work you need to config it within hardhat.config like so
etherscan: {
apiKey: ETHERSCAN_API_KEY,
},
You can directly verify a contract thru command line like so
yarn hardhat verify --network mainnet DEPLOYED_CONTRACT_ADDRESS "Constructor arguements"
If you'd like to verify your contract programtically through a script use run run package.
async function verify(contractAddress, args) {
console.log("Verifying contract ...")
try {
await run("verify:verify", {
address: contractAddress,
constructorArguments: args,
})
} catch (e) {
if (e.message.toLowerCase().includes("already verified")) {
console.log("Already Verified!")
} else {
console.log(e)
}
}
//run (first parameter is the subtask of our verify task, second parameter is the object with actual parameters)
}
Basic Testing with hardhat (mochajs)
to get started we create a descibe function. That takes two parameters the name of test and a function
describe("SimpleStorage", function () {}
inside each descibe blocks we will have a beforeEach function.
beforeEach - used to set up data before testing occurs
in this instants we set up the smart contract
describe("SimpleStorage", function () {
let simpleStorageFactory, simpleStorage
beforeEach(async function () {
simpleStorageFactory = await ethers.getContractFactory("SimpleStorage")
simpleStorage = await simpleStorageFactory.deploy()
})
}
After before each it is then used to test specific things within the smart contract
it - takes two parameters one descibing the current test and the second is a function where test takes place
in this instants we are testing simplestorage to start with favorite number as 0
it("should start with a favorite number of 0", async function () {
const currentValue = await simpleStorage.favoriteNumber()
console.log(currentValue)
const expectedValue = "0"
assert.equal(currentValue.toString(), expectedValue)
})
next to use assert or expect to determine if the test is correct u must import chai chai docs
yarn add --dev chai
to check if two values equal each other u can use assert.equal()
assert.equal(currentValue.toString(), expectedValue)
you can do the same with expect like so
expect(currentValue.toString()).to.equal(expectedValue)
to run test use
yarn hardhat test
if you'd like to test one specific case use use --grep and text that resides within name of it()
yarn hardhat test --gerp "should start with a favorite number of 0"
Coverage
Coverage task is used to check the tests we created for our smart contract and see if we tested all functions and there corrasponding variables. It will tell us what lines have not been tested for
add to hardhat config file
require("solidity-coverage")
example out put
---------------------|----------|----------|----------|----------|----------------|
File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
---------------------|----------|----------|----------|----------|----------------|
contracts/ | 33.33 | 100 | 50 | 33.33 | |
SimpleStoreage.sol | 33.33 | 100 | 50 | 33.33 | 63,66 |
---------------------|----------|----------|----------|----------|----------------|
All files | 33.33 | 100 | 50 | 33.33 | |
---------------------|----------|----------|----------|----------|----------------|
Gas Reporter
Add gas reporter to your project
yarn add --dev hardhat-gas-reporter
Next you need to config gas reporter in your hardhat.config.js. This is basic setup that will print gas report to console.
gasReporter: {
enabled: true,
},
if you want to go a step further you can output the gas reporter to a file and add the USD price of the gas. To actually get the price in USD we need a coinmarket cap api key
gasReporter: {
enabled: true,
outputFile: "gas-report.txt",
noColors: true,
currency: "USD",
coinmarketcap: COINMARKCAP_API_KEY,
//change block chain to see gas prices
// token: "AVAX",
},
gas report will look something like this
| Solc version: 0.8.9 · Optimizer enabled: false · Runs: 200 · Block limit: 30000000 gas │
································|····························|·············|······························
| Methods · 15 gwei/gas · 1921.97 usd/eth │
··················|·············|··············|·············|·············|···············|··············
| Contract · Method · Min · Max · Avg · # calls · usd (avg) │
··················|·············|··············|·············|·············|···············|··············
| SimpleStorage · addPerson · - · - · 112395 · 2 · 3.24 │
··················|·············|··············|·············|·············|···············|··············
| SimpleStorage · store · - · - · 43724 · 2 · 1.26 │
··················|·············|··············|·············|·············|···············|··············
| Deployments · · % of limit · │
································|··············|·············|·············|···············|··············
| SimpleStorage · - · - · 463034 · 1.5 % · 13.35 │
·-------------------------------|--------------|-------------|-------------|---------------|-------------·