/truffle-cheatsheet

Truffle spreadsheet

Connect to ganache console

truffle console --network ganache

Migrate and reset

truffle migrate --compile-all --reset

Get loaded contract instance

// replace CONTRACT_NAME with your value
<CONTRACT_NAME>.deployed().then((app) => { app = app; })

// example
ChainList.deployed().then((app) => { app = app; })

Get loaded accounts

web3.eth.getAccounts().then((accounts) => { accounts = accounts; })

Money converter

// will return 3 ethers properly casted to long value
web3.utils.toWei('3', 'ether')

// similar, in case you are working with integer value
web3.utils.toWei(web3.utils.toNB(3), 'ether')

Get account balance

// promise to wei-value, ex. 9967918....
web3.eth.getBalance(accounts[0])

// pretty-print, ex 99.679
we3.eth.getBalance(accounts[0]).then((balance) => { balance = balance.toString() });
web3.utils.fromWei(balance, "ether")

Calling contract with parameters

// working with deployed instance of a contract below 
app.sellArticle("iPhone", "Selling in order to buy iPhone 8", web3.utils.toWei("3", "ether"), { from: accounts[1] })

Listening to event defined in contract

app.contract.events.LogSellArticle({fromBlock: 0}, (error, event) => { console.log(event); })

Loading already happen events

const events = await app.contract.getPastEvents("LogSellArticle", { fromBlock: 0 });

Running web3-js on create-react-app and react-script@5.x.x (webpack 5.x.x.)

If you have a lot of errors, devoted to impossibility to resolve different libs, such as buffer, scrypt, assert and so on, this paragraph is for you.

Steps to fix:

  1. Install react-app-rewired and make it works

  2. Install all packages:

    npm install stream-http https-browserify crypto-browserify scrypt-js buffer stream-browserify os-browserify url assert

  3. In config-overrides.js add those lines:

    const loaders = config.resolve;

loaders.fallback = {
   http: require.resolve("stream-http"),
   https: require.resolve("https-browserify"),
   crypto: require.resolve("crypto-browserify"),
   scrypt: require.resolve("scrypt-js"),
   buffer: require.resolve("buffer"),
   stream: require.resolve("stream-browserify"),
   os: require.resolve("os-browserify/browser"),
   url: require.resolve("url"),
   assert: require.resolve("assert"),
}

config.plugins.push(
 new webpack.ProvidePlugin({
   Buffer: ["buffer", "Buffer"],
   process: "process/browser",
 })
);

Geth - unlock password error while truffle migrate

*Make sure you are running geth instance *Geth attach *personal.unlockAccount("ACCOUNT_ADDRESS") *provide account password *True is printed if successfully unlocked

Geth - making new account

geth --datadir PATH_TO_PRIVATE_FOLDER account new

Geth - getting balance account

eth.getBalance(eth.accounts[0])

# pretty-print
web3.fromWei(eth.getBalance(eth.accounts[0]))