compile.js

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

const sourceFolderPath = path.resolve(__dirname, 'contracts');
const buildFolderPath = path.resolve(__dirname, 'build/contracts');


const getContractSource = contractFileName => {
    const contractPath = path.resolve(__dirname, 'contracts', contractFileName);
    return fs.readFileSync(contractPath, 'utf8');
};

let sources = {};

let walk = function (dir) {
    let results = [];
    let list = fs.readdirSync(dir);
    list.forEach(function (file) {
        file = dir + '/' + file;
        let stat = fs.statSync(file);
        if (stat && stat.isDirectory()) {
            results = results.concat(walk(file));
        } else {
            if (file.substr(file.length - 4, file.length) === ".sol") {
                sources[file] = {
                    content: getContractSource(file)
                }
            }
            results.push(file);
        }
    });
    return results;
};
walk(sourceFolderPath);

const input = {
    language: 'Solidity',
    sources,
    settings: {
        outputSelection: {
            '*': {
                '*': ['*']
            }
        }
    }
};

console.log('\nCompiling contracts...');
const output = JSON.parse(solc.compile(JSON.stringify(input)));
console.log('Done');

let shouldBuild = true;

if (output.errors) {
    console.error(output.errors);
    // throw '\nError in compilation please check the contract\n';
    for (error of output.errors) {
        if (error.severity === 'error') {
            shouldBuild = false;
            throw 'Error found';
            break;
        }
    }
}

if (shouldBuild) {
    console.log('\nBuilding please wait...');

    fs.removeSync(buildFolderPath);
    fs.ensureDirSync(buildFolderPath);

    for (let contractFile in output.contracts) {
        for (let key in output.contracts[contractFile]) {
            fs.outputJsonSync(
                path.resolve(buildFolderPath, `${key}.json`),
                {
                    abi: output.contracts[contractFile][key]["abi"],
                    bytecode: output.contracts[contractFile][key]["evm"]["bytecode"]["object"]
                },
                {
                    spaces: 2,
                    EOL: "\n"
                }
            );
        }
    }
    console.log('Build finished successfully!\n');
} else {
    console.log('\nBuild failed\n');
}