Bdtjtk

When trying to compile the smart contract with solc-js I was getting the error

Krishna:Voting krishnakankipati$ node deploy.js
Compiling the contract
assert.js:350
throw err; ^

AssertionError [ERR_ASSERTION]: Invalid callback specified.

let compilerInput = {

     'Voter': fs.readFileSync('Voter.sol', 'utf8')

};



console.log('Compiling the contract')

// Compile and optimize the contract

let compiledContract = solc.compile(compilerInput, 1);



// Get compiled contract

let contract = compiledContract.contracts['Voter:Voter'] // Voter contract from Voter file.



 // Save contract's ABI

let abi = contract.interface;

fs.writeFileSync('abi.json', abi);

Please be sure to read the solc docs for solc v0.5.0+ to ensure you're adjusting for the changes to the Solidity compiler.

Something like this should be compatible with the latest version of solc:

// Note: You should be defining your contract sources as objects now.

// Note: You must also provide the compiler output selection as well.

const compilerInput = {

    language: "Solidity",

    sources: {

        'Voter': { content: fs.readFileSync('Voter.sol', 'utf8') }

    },

    settings: {

      outputSelection: {

        "*": {

          "*": [ "abi", "evm.bytecode" ]

        }

      }

    }

};



console.log('Compiling the contract')

// Note: You have to pass the input in with JSON.stringify now.

const compiledContract = JSON.parse(solc.compile(JSON.stringify(compilerInput)));



if(compiledContract.errors) {

    compiledContract.errors.forEach(err => console.log(err.formattedMessage));

}



// Note: This changed slightly since I'm using JSON.parse above.

const contract = compiledContract.contracts['Voter'].Voter; // Voter contract from Voter file.



// Note: This is now called 'abi' and not 'interface'

const abi = contract.abi;

fs.writeFileSync('abi.json', JSON.stringify(abi, null, 2));

You'll also need to update your deployContract function to be in sync with solc v0.5.0+

async function deployContract(web3, contract, sender) {

    let Voter = new web3.eth.Contract(JSON.parse(JSON.stringify(abi)));

    let bytecode = '0x' + contract.evm.bytecode.object;

    let gasEstimate = await web3.eth.estimateGas({data: bytecode});



    // The rest should work fine...

}

You aren't using solc-js correctly. You need to stringify the input, and you're passing a 1 instead of an import callback. Please read the docs before posting questions: https://github.com/ethereum/solc-js

Consider using etherjs, much better documentation and more robust than web3.