Development tools setup (Hardhat, Remix) in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize a new Hardhat project.

Blockchain / Solidity

npx hardhat [1]

Drag options to blanks, or click blank then click option'

Astart

Bcreate

Cinit

Dnew

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'create' or 'start' instead of 'init'.

Use npx hardhat init to initialize a new Hardhat project.

2fill in blank

medium

Complete the code to compile contracts using Hardhat.

Blockchain / Solidity

npx hardhat [1]

Drag options to blanks, or click blank then click option'

Adeploy

Bcompile

Ctest

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'deploy' or 'test' instead of 'compile'.

The compile command compiles Solidity contracts in Hardhat.

3fill in blank

hard

Fix the error in the Hardhat config file to specify the Solidity version.

Blockchain / Solidity

module.exports = {
  solidity: '[1]'
};

Drag options to blanks, or click blank then click option'

A'0.8.0'

B"0.8.0"

C0.8.0

Dversion: '0.8.0'

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving the version unquoted or adding extra keys.

The Solidity version must be a string in quotes, like '0.8.0'.

4fill in blank

hard

Fill both blanks to run a local Hardhat node and deploy contracts.

Blockchain / Solidity

npx hardhat [1] & npx hardhat [2]

Drag options to blanks, or click blank then click option'

Anode

Bcompile

Crun

Dtest

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'test' or 'compile' instead of 'run' for deployment.

Use node to start the local blockchain and run to deploy scripts.

5fill in blank

hard

Fill all three blanks to connect Remix IDE to a local Hardhat node.

Blockchain / Solidity

In Remix, select [1] environment, set the [2] URL to http://localhost:[3].

Drag options to blanks, or click blank then click option'

AInjected Web3

BWeb3 Provider

C8545

D3000

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'Injected Web3' or wrong port number.

Use the Web3 Provider environment in Remix and set the URL to http://localhost:8545 to connect to Hardhat.

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