Examples

Practical examples and workflows using Mega CLI

Examples

This section provides practical examples and complete workflows to help you get the most out of Mega CLI.

Smart Contract Development Workflow

This example shows a complete workflow for developing, testing, and deploying a smart contract locally and to MegaETH testnet.

1. Initialize a Foundry Project

# Create a new Foundry project
mega init my-contract-project --foundry

# Navigate to the project
cd my-contract-project

2. Create a Simple Contract

Create a file named src/Counter.sol:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Counter {
    uint256 private counter;
    
    event CounterIncremented(address indexed user, uint256 newValue);
    
    function getCount() public view returns (uint256) {
        return counter;
    }
    
    function increment() public {
        counter += 1;
        emit CounterIncremented(msg.sender, counter);
    }
}

3. Write a Test

Create a file named test/Counter.t.sol:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "forge-std/Test.sol";
import "../src/Counter.sol";

contract CounterTest is Test {
    Counter public counter;
    
    function setUp() public {
        counter = new Counter();
    }
    
    function testInitialCount() public {
        assertEq(counter.getCount(), 0);
    }
    
    function testIncrement() public {
        counter.increment();
        assertEq(counter.getCount(), 1);
    }
    
    function testEmitsEvent() public {
        vm.expectEmit(true, false, false, true);
        emit Counter.CounterIncremented(address(this), 1);
        counter.increment();
    }
}

4. Compile and Test

# Compile contracts
mega compile

# Run tests
forge test

5. Deploy Locally

You can use the mega deploy command like so:

# Deploy to local network (the default)
mega deploy src/Counter.sol:Counter --broadcast

For more complex deployment scenarios, you can still create deployment scripts in the script/ directory, but for this example, we’ll use the direct deployment approach.

6. Create an Account

# Create a new account
mega account create
# > Enter a name for your wallet: dev
# > Enter a password: ********

7. Get Testnet Tokens

# Request tokens from the faucet
mega faucet --account <account-name>

8. Deploy to Testnet

# Deploy to MegaETH testnet
mega deploy src/Counter.sol:Counter --network testnet --broadcast --account <account-name>

9. Deploy to Mainnet

When you are ready and have a funded MegaETH mainnet account:

mega deploy src/Counter.sol:Counter --network mainnet --broadcast --account <account-name>

You can override a network’s default RPC while retaining chain ID validation:

mega deploy src/Counter.sol:Counter \
  --network mainnet \
  --rpc-url https://your-mainnet-rpc.example \
  --broadcast \
  --account <account-name>

Full-Stack App Development Workflow

This example demonstrates how to create and run a full-stack application.

1. Initialize a Full-Stack Project

# Create a new full-stack project
mega init my-dapp

# Navigate to the project
cd my-dapp

2. Start the Development Environment

# Start both the Foundry and frontend environments
mega dev

3. Deploy a Contract to the Local Chain

In a new terminal:

# Compile contracts
mega compile

# Deploy to local Anvil chain (uses default Anvil private key)
mega deploy foundry-app/src/GmegaCounter.sol:GmegaCounter --broadcast

4. Connect the Frontend to the Contract

Update next-app/src/constants/index.js with your contract address:

export const CONTRACT_ADDRESSES = {
  GmegaCounter: "0x5FbDB2315678afecb367f032d93F642f64180aa3" // Replace with your deployed address
};

5. Test the Application

After starting the development environment with mega dev, you can:

1. Visit http://localhost:3000/gmega in your browser
2. Connect your wallet
3. Interact with the deployed contract