1

I am trying to follow a tutorial available at: medium Just Dev

> getBalance = web3.eth.getBalance
> balanceInEth = address => web3.fromWei(getBalance(address).toString())

I got errors so I used the following command:

> getBalance = web3.eth.getBalance;"Testing"
'Testing'
truffle(development)> balanceInEth = async(address) => web3.utils.fromWei(await     web3.eth.getBalance(address))

But they are generating huge error:

Thrown: TypeError: Cannot read property 'match' of undefined at ReadStream.onData (readline.js:1073:36) at emitKeys.next () at emitKeys (internal/readline.js:424:14) at ReadStream.EventEmitter.emit (domain.js:448:20) at ReadStream.emit (events.js:198:13)

I was told to use following command at:

Error Truffle Console: web3.fromWei is not a function

truffle(ganache)> web3.eth.getAccounts(function(err, acc) { accounts = acc });
truffle(ganache)> const boo = async () => { return web3.utils.fromWei(await web3.eth.getBalance(accounts[0]), 'ether'); }
truffle(ganache)> boo()
'99.0015542'

The above commands are printing the account values for acc1, victim and attacker but when I am executing the transaction for victim, I am getting a huge error message:

truffle(development)> options = { from: acc1, to : victim.address,
 value: web3.utils.toWei('11', 'ether')}

{ from: [AsyncFunction: acc1], to: '0xA3339bb424303D6F58B1260872c9C2DBF840e771', value: '11000000000000000000' }

truffle(development)> victim.deposit.sendTransaction(options) 

Thrown: { Error: Returned error: from not found; is required at evalmachine.:0:16 at sigintHandlersWrap (vm.js:288:15) at Script.runInContext (vm.js:130:14) at runScript (/home/zulfi/.nvm/versions/node/v10.22.0/lib/node_modules/truffle/build/webpack:/packages/core/lib/console.js:227:1)

Somebody please guide me how to print account values on truffle console.

Zulfi.

2

Truffle v5 uses web3 v1.x which is fully async. For all calls that interact with the blockchain use await in front.

truffle(develop)> accounts = await web3.eth.getAccounts()
undefined
truffle(develop)> accounts
[
  '0xe2aa116DDD9A562895A7DeFa3eb8049a28Ce04B0',
  '0x28Da3F02B460F303FD161F6f3406cE9070aF8710',
  '0x63d666a8421a45119A63787400dD6bdF0C91bB57',
  '0x87955E85f8ce170496ebdAa9f3086d49E56a6Cbd',
  '0x750949866E7661AdcE549521772eebAAfd8a6021',
  '0x99d4D496FabE5E0A9F4A77989C65cdb16D46A0a6',
  '0x71E25Cf3Ed1845f43b977aA2C69CaC7217C2B229',
  '0xb92De65298cEe8716b708203A47260f8137a0886',
  '0x927417c6E16FE04Cde5d77bB862EFE8f1862c105',
  '0x865c34ad3b703B1e24d4493b3249067A764FB1D9'
]

To obtain the balance

truffle(develop)> acc1 = accounts[1]
'0x28Da3F02B460F303FD161F6f3406cE9070aF8710'
truffle(develop)> balance1 = await web3.eth.getBalance(acc1)
undefined
truffle(develop)> web3.utils.fromWei(balance1, "ether")
'100'

If you forget to use await the result will be a Promise instead of the real value.

Looking at the error message from: [AsyncFunction: acc1] the value used as from acc1 is a promise, and the functions fails because it is expecting an address instead.

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