Development tools setup (Hardhat, Remix) in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Hardhat in blockchain development?

Hardhat is a development environment to compile, deploy, test, and debug Ethereum smart contracts easily on a local blockchain network.

beginner

What is Remix IDE used for?

Remix is a web-based IDE that allows you to write, compile, deploy, and debug smart contracts directly in the browser without setup.

intermediate

Name one advantage of using Hardhat over Remix.

Hardhat allows local blockchain simulation and automated testing with scripts, which is better for complex projects than Remix's browser environment.

beginner

Which command initializes a new Hardhat project?

The command is npx hardhat, which starts a setup wizard to create a Hardhat project.

beginner

How do you run tests in a Hardhat project?

You run tests by executing npx hardhat test in the project directory.

What is the main purpose of Remix IDE?

A Write and test smart contracts in the browser

B Simulate a local blockchain network

C Deploy smart contracts to Bitcoin network

D Create frontend web apps

Remix IDE is a browser-based tool for writing and testing Ethereum smart contracts.

Which command starts the Hardhat setup wizard?

A npx hardhat

B npm install hardhat

C hardhat init

D hardhat start

Running npx hardhat launches the Hardhat project setup wizard.

Which tool allows automated testing with scripts?

A Remix

B MetaMask

C Ganache

D Hardhat

Hardhat supports automated testing with scripts in a local blockchain environment.

Where does Remix IDE run?

A Locally on your computer only

B In the browser

C On a remote server only

D Inside a mobile app

Remix is a web-based IDE that runs in the browser.

How do you run tests in Hardhat?

A hardhat run tests

B npm test

C npx hardhat test

D remix test

The command npx hardhat test runs tests in a Hardhat project.

Explain the main differences between Hardhat and Remix for smart contract development.

Think about where each tool runs and what features they offer.

Describe the steps to set up a new Hardhat project from scratch.

Focus on commands and what happens during setup.

Practice

1. Which of the following best describes Hardhat in blockchain development?

easy

A. A hardware device to store private keys securely

B. A local development environment to write and test smart contracts

C. An online marketplace for buying cryptocurrencies

D. A blockchain explorer to view transactions

Solution

1. Step 1: Understand Hardhat's purpose

   Hardhat is designed as a local tool to help developers write, test, and deploy smart contracts easily on their computer.

2. Step 2: Compare options with Hardhat's role

   Options A, B, and D describe other blockchain tools or devices, not Hardhat.

3. Final Answer:

   A local development environment to write and test smart contracts -> Option B

4. Quick Check:

   Hardhat = Local development tool [OK]

Hint: Hardhat runs locally for coding and testing smart contracts [OK]

Common Mistakes:

• Confusing Hardhat with hardware wallets
• Thinking Hardhat is an online platform
• Mixing Hardhat with blockchain explorers

2. Which command correctly initializes a new Hardhat project in your terminal?

easy

A. npx hardhat

B. npx hardhat init

C. hardhat start

D. hardhat create project

Solution

1. Step 1: Recall Hardhat initialization command

   The standard way to start a Hardhat project is by running npx hardhat which launches the setup wizard.

2. Step 2: Evaluate other options

   Options A, B, and C are not valid Hardhat commands for project initialization.

3. Final Answer:

   npx hardhat -> Option A

4. Quick Check:

   Initialize Hardhat with 'npx hardhat' [OK]

Hint: Use 'npx hardhat' to start a new project setup [OK]

Common Mistakes:

• Using 'hardhat create project' which is invalid
• Trying 'hardhat start' instead of 'npx hardhat'
• Using 'npx hardhat init' which is not a valid command

3. What will be the output when you run this Hardhat command in a new project folder?

npx hardhat compile

medium

A. Starts a local blockchain node

B. Throws an error: command not found

C. Deletes all compiled files

D. Compiles smart contracts and shows success message

Solution

1. Step 1: Understand the 'compile' command in Hardhat

   The command npx hardhat compile compiles all smart contracts in the project and outputs success or error messages.

2. Step 2: Check other options

   Throws an error: command not found is wrong because the command exists. Deletes all compiled files is incorrect as it does not delete files. Starts a local blockchain node is for running nodes, not compiling.

3. Final Answer:

   Compiles smart contracts and shows success message -> Option D

4. Quick Check:

   'npx hardhat compile' compiles contracts [OK]

Hint: Compile contracts with 'npx hardhat compile' to check code [OK]

Common Mistakes:

• Expecting 'compile' to start blockchain node
• Thinking 'compile' deletes files
• Assuming command is invalid without setup

4. You tried to deploy a contract using Hardhat but got this error:
Error: Cannot find module '@nomiclabs/hardhat-ethers'
What is the most likely fix?

medium

A. Install the missing plugin with npm install --save-dev @nomiclabs/hardhat-ethers

B. Restart your computer

C. Delete the node_modules folder without reinstalling

D. Run npx hardhat compile again

Solution

1. Step 1: Identify the missing module error

   The error says the plugin '@nomiclabs/hardhat-ethers' is missing, meaning it is not installed in the project.

2. Step 2: Fix by installing the missing plugin

   Running npm install --save-dev @nomiclabs/hardhat-ethers adds the plugin so Hardhat can use it.

3. Final Answer:

   Install the missing plugin with npm install --save-dev @nomiclabs/hardhat-ethers -> Option A

4. Quick Check:

   Missing module error = install plugin [OK]

Hint: Install missing packages with npm to fix module errors [OK]

Common Mistakes:

• Restarting computer without installing packages
• Deleting node_modules without reinstalling
• Running compile without fixing dependencies

5. You want to quickly test a simple smart contract without installing anything locally. Which tool should you use and why?

hard

A. Use Hardhat because it runs in the browser without installation

B. Use a hardware wallet to write contracts securely

C. Use Remix because it is an online editor that requires no local setup

D. Use a blockchain explorer to deploy contracts

Solution

1. Step 1: Identify tools for quick testing without local setup

   Remix is an online IDE that lets you write, compile, and deploy contracts directly in the browser.

2. Step 2: Compare with other options

   Hardhat requires local installation, hardware wallets store keys but don't write contracts, and blockchain explorers only view data.

3. Final Answer:

   Use Remix because it is an online editor that requires no local setup -> Option C

4. Quick Check:

   Quick test without install = Remix online editor [OK]

Hint: Remix runs in browser, no install needed for quick tests [OK]

Common Mistakes:

• Thinking Hardhat runs in browser without install
• Confusing hardware wallets with development tools
• Trying to deploy contracts via blockchain explorers