npm solc: AssertionError [ERR_ASSERTION]: Invalid callback specified

Question

I am trying to compile solidity smart contract using npm solc. I tried to follow different examples. Link to example: https://medium.com/coinmonks/how-to-compile-a-solidity-smart-contract-using-node-js-51ea7c6bf440

I wrote my code like following:

const path = require('path');
const fs = require('fs');
const solc = require('solc');



const helloPath = path.resolve(__dirname, 'contracts', 'hello.sol');
console.log("First" + helloPath);
const source = fs.readFileSync(helloPath, 'UTF-8');
console.log("Second" + source);
console.log(solc.compile(source, 1));

I am getting following error when running the above code.

AssertionError [ERR_ASSERTION]: Invalid callback specified.
    at wrapCallback (C:\Users\mouazzamj058\solc_example\node_modules\solc\wrapper.js:16:5)
    at runWithReadCallback (C:\Users\mouazzamj058\solc_example\node_modules\solc\wrapper.js:37:42)
    at compileStandard (C:\Users\mouazzamj058\solc_example\node_modules\solc\wrapper.js:78:14)
    at Object.compileStandardWrapper (C:\Users\mouazzamj058\solc_example\node_modules\solc\wrapper.js:85:14)
    at Object.<anonymous> (C:\Users\mouazzamj058\solc_example\example.js:4:19)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)

Please help.

Are you sure this error is from `solc`. Can you debug and see where exactly you get the error from? — nikos fotiadis, Nov 17 '18 at 20:28

score 50 · Accepted Answer · answered Nov 17 '18 at 17:36

50

Which version of solc are you using?

Solc released a breaking version the other day, this error is related to that.

npm uninstall solc
npm install solc@0.4.25

answered Nov 17 '18 at 17:36

Falko

995
11
21

score 48 · Answer 2 · answered Jun 23 '19 at 14:09

If you are using latest version ie. 0.5.9 there is change in how you compile the code.

const path = require('path');
const fs = require('fs');
const solc = require('solc');



const helloPath = path.resolve(__dirname, 'contracts', 'hello.sol');
const source = fs.readFileSync(helloPath, 'UTF-8');

var input = {
    language: 'Solidity',
    sources: {
        'hello.sol' : {
            content: source
        }
    },
    settings: {
        outputSelection: {
            '*': {
                '*': [ '*' ]
            }
        }
    }
}; 
console.log(JSON.parse(solc.compile(JSON.stringify(input))));

This should be the accepted answer simply downgrading the version is not a solution — Shazil Sattar, Jun 22 '22 at 18:02

score 6 · Answer 3 · answered Jan 09 '19 at 13:03

This is because of version mismatch of solidity compiler installed during solc package installation and the compiler mentioned in the solidity file.To solve this issue try

install:

npm install solc@0.4.25

in solidity file use :

pragma solidity^0.4.25;

score 4 · Answer 4 · edited Feb 07 '19 at 00:13

4

This is because the version mismatch of Solidity compiler. Please note or verify the solidity compiler version in which you want to work. For example: If you are doing work in

pragma solidity ^0.4.17

then you have to install 0.4.17 solidity compiler version like this:

npm install solc@0.4.17

in the command prompt or terminal.

edited Feb 07 '19 at 00:13

Roman Pokrovskij

9,449
21
87
142

answered Feb 06 '19 at 23:33

Rayed Bin Aslam

41
1

score 4 · Answer 5 · answered Sep 08 '20 at 06:59

with solc 0.7.1:


function compileContract() {
    let voterSOl = fs.readFileSync('./contracts/voter.sol' , 'utf8')
    let complierInput = {
        language: 'Solidity',
        sources:
        {
            'voter.sol': 
            {
                content: voterSOl
            }
        },
        settings:
        {
            optimizer:
            {
                enabled: true
            },
            outputSelection:
            {
                '*':{
                    '*':['*']
                }
            }
        }
    };
    console.log('compiling contract');
    let compiledContract = JSON.parse(solc.compile(JSON.stringify(complierInput)));
    console.log('Contract Compiled');
    for (let contractName in compiledContract.contracts['voter.sol']) {
        console.log(contractName , compiledContract.contracts['voter.sol'][contractName].abi);      
        let abi = compiledContract.contracts['voter.sol'][contractName].abi;
        fs.writeFileSync(`./contracts/bin/${contractName}_abi.json` , JSON.stringify(abi));
        return compiledContract.contracts['voter.sol'][contractName];
    }
}

score 3 · Answer 6 · answered Jun 30 '19 at 02:04

3

If you have see error like this.You must do following two steps.

Uninstall solc:

npm uninstall solc
Reinstall one of two versions:

The version used in the course:

npm install --save solc@0.4.17

or

The newest version that will not break:

npm install --save solc@0.4.25

source - Udemy - Ethereum and Solidity The Complete Developer's Guide

answered Jun 30 '19 at 02:04

Sulakshitha Rathnayake

61
5

but going foward – erod Aug 08 '21 at 01:57

score 1 · Answer 7 · answered May 19 '19 at 13:58

This is generally the assertion error between the solidity compiler that you have installed and the solidity compiler version that you are using in the solidity contract file. If you are using

npm install --save solc@0.4.25

to install solc in your mac then, please use the same version of pragma in your solidity file like the following

pragma solidity^0.4.25

score 1 · Answer 8 · answered May 18 '20 at 12:22

1

I fixed the error with adding "npm install --save solc@0.4.25" in cmd. Error is the solidity version. you need to install old version of solidity to execute the compile script

answered May 18 '20 at 12:22

Sachintha Weesinghe

11
1

score 1 · Answer 9 · answered Oct 11 '22 at 11:49

sol ver: 0.8.17

Compile:

const path = require('path');
const solc = require('solc');
const fs = require('fs-extra');

const buildPath = path.resolve(__dirname, 'build');
fs.removeSync(buildPath);

const campaignPath = path.resolve(__dirname, 'contracts', 'Campaign.sol');
const source = fs.readFileSync(campaignPath, 'UTF-8');

var input = {
    language: 'Solidity',
    sources: {
        'Campaign.sol' : {
            content: source
        }
    },
    settings: {
        outputSelection: {
            '*': {
                '*': [ '*' ]
            }
        }
    }
};

var output = JSON.parse(solc.compile(JSON.stringify(input)));
fs.ensureDirSync(buildPath);

for(contractName in output.contracts['Campaign.sol']){
    fs.outputJSONSync(
        path.resolve(buildPath, contractName + '.json'),
        output.contracts['Campaign.sol'][contractName]
    );
}

Deploy:

const HDWalletProvider = require('@truffle/hdwallet-provider');
const Web3 = require('web3');
const compiledFactory = require('./build/CampaignFactory.json');

const provider = new HDWalletProvider(
    process.env.NEXT_PUBLIC_META_MASK,
    process.env.NEXT_PUBLIC_INFURA_API
);

const web3 = new Web3(provider);

const deploy = async () => {
    const accounts = await web3.eth.getAccounts();
    console.log('attempting to deploy from account: ', accounts[0]);

    const result = await new web3.eth.Contract(compiledFactory.abi)
    .deploy({data: compiledFactory.evm.bytecode.object})
    .send( {from:accounts[0], gas:'3000000'});

    console.log('Contract deployed to: ', result.options.address);
    provider.engine.stop();
};

deploy();

score 0 · Answer 10 · answered Feb 01 '19 at 14:45

0

Check your code in Remix first, then check compiler version

answered Feb 01 '19 at 14:45

Russo

2,186
2
26
42

score 0 · Answer 11 · answered Dec 26 '19 at 06:39

0

unistall solidity compiler
using - npm uninstall solc
then install required version of solidity compiler
using - npm install solc@0.4.17

answered Dec 26 '19 at 06:39

Ramu

11
2

score 0 · Answer 12 · answered Oct 11 '21 at 06:11

0

Remember to check solidity version and solc version . They should be equal.

answered Oct 11 '21 at 06:11

subhajit das

383
3
8

score 0 · Answer 13 · answered Oct 30 '21 at 13:49

Basically, it's a version issue. Some code syntax will change on each update. You don't need the 'filesystem' and 'path' libraries. To solve this issue, try this code:

const solc = require('solc');

var input = {
    language: 'Solidity',
    sources: {
        'hello.sol': {
            content: 'contract hello { function f() public { } }'
        }
    },
    settings: {
        outputSelection: {
            '*': {
                '*': ['*']
            }
        }
    }
};

var output = JSON.parse(solc.compile(JSON.stringify(input)));
console.log(output);

From this, you will get bytecode.

score 0 · Answer 14 · answered Dec 07 '21 at 22:38

0

The version of Solidity you are using and the solidity compiler(solc) you are using should be same .

If pragma solidity^0.4.17 then solc-->version = 0.4.17

answered Dec 07 '21 at 22:38

MohitHustler

61
1
4

score 0 · Answer 15 · answered Jun 12 '22 at 02:07

sol version 0.8.6

const path = require('path');
const solc = require('solc');
const fs = require('fs-extra');

const buildPath = path.resolve(__dirname, 'build');
fs.removeSync(buildPath); // remove build folder

// Read 'hello.sol' file from the 'contracts' folder
const helloPath = path.resolve(__dirname, 'contracts', 'hello.sol');
const source = fs.readFileSync(helloPath, 'utf8');

var input = {
    language: 'Solidity',
    sources: {
        'hello.sol': {
            content: source
        }
    },
    settings: {
        outputSelection: {
            '*': {
                '*': ['*']
            }
        }
    }
};


var output = JSON.parse(solc.compile(JSON.stringify(input)));

fs.ensureDirSync(buildPath); // ensure build folder exists

for (let contract in output) {
    fs.outputJSONSync(
        path.resolve(buildPath, contract + '.json'),
        output[contract]
    );
}

npm solc: AssertionError [ERR_ASSERTION]: Invalid callback specified

15 Answers15

npm install solc@0.4.25

pragma solidity^0.4.25;

Linked