// Mini course
Lesson 04: Interact with MetaCoin Using Web3
After deployment, you can inspect accounts, check balances, and send MetaCoin from one address to another in the Truffle console. The PDF explains that MetaCoin starts by assigning the transaction origin an initial balance of 10000 MetaCoin in the constructor. fileciteturn0file0
📦 Download the complete MetaCoin project used in this tutorial from GitHub:
Download the MetaCoin Truffle Project
Download the MetaCoin Truffle Project
Enter the console and inspect accounts
truffle develop
migrate --reset
web3.eth.getAccounts()
You can access individual accounts such as accounts[0] and accounts[1].
Check Ether balance
web3.eth.getBalance(accounts[0])
web3.fromWei(web3.eth.getBalance(accounts[0]), 'ether')
Balances returned by web3.eth.getBalance() are in Wei. The PDF reminds readers that 1 Ether = 1018 Wei. fileciteturn0file0
Check MetaCoin balance
MetaCoin.deployed().then(function(instance){
return instance.getBalance.call(accounts[0]);
}).then(function(value){
return value.toNumber();
});
Send MetaCoin
MetaCoin.deployed().then(function(instance) {
return instance.sendCoin(accounts[1], 1000, {from: accounts[0]});
});
After sending, check both balances again to confirm that the transfer worked.
Optional: debug a transaction
The PDF also introduces the Truffle debugger using a transaction hash:
debug '0xYOUR_TRANSACTION_HASH'
You can watch values such as receiver and amount while stepping through the transaction.