Validate email domains of prospects to ensure they are deliverable using Autohost API

validate.js

const csv = require('@fast-csv/parse');
const https = require('https');

// Autohost API client
const client = (path, data, method = 'GET') => {
    return new Promise((resolve, reject) => {
        const options = {
            method,
            hostname: 'data.autohost.ai',
            port: 443,
            protocol: 'https:',
            path,
            headers: {
                'x-api-key': 'ENTER-YOUR-API-KEY',
            }
        };
        const req = https.request(options, res => {
            const chunks = [];
            res.setEncoding('utf8');
            res.on('data', chunk => chunks.push(chunk));
            res.on('end', () => {
                let body = chunks.join('');
                const status = res.statusCode;
                if (status >= 400) {
                    return reject(body);
                }
                try {
                    body = JSON.parse(body);
                } catch (error) {
                    // console.log(error);
                }
                return resolve(body);
            });
        });
        req.on('error', error => reject(error));
        if (data) {
            try {
                data = JSON.stringify(data);
                req.setHeader('Content-Type', 'application/json');
                req.write(data);
            } catch (e) {
                console.error(e);
            }
        }
        req.end();
    });
};

// validate email address on Autohost
const emailValidation = async (email) => {
    let res;
    try {
        res = await client(`/v1/validate/email/${encodeURIComponent(email)}`);
    }
    catch (error) {
        console.log(error);
    }
    return res;
};

// load emails from CSV file and return list of unique domains
const parseCSV = () => new Promise((resolve, reject) => {
    const domains = {};
    csv.parseFile('./leads.csv', { headers: true })
        .on('error', error => console.error(error))
        .on('data', async (row) => {
            const email = row.email;
            const domain = email.split('@')[1].trim();
            domains[domain] = domains[domain] ? domains[domain] + 1 : 1;
        })
        .on('end', () => resolve(Object.keys(domains)));
});

// main handler
const main = () => {
    const invalid = [];
    (async () => {
        const domains = await parseCSV();
        console.log(`Total unique domains: ${domains.length}`);
        for (let i = 0; i < domains.length; i++) {
            const domain = domains[i];
            const res = await emailValidation(`test@${domain}`);
            if (res) {
                if (res.status === 'INVALID') {
                    console.log(`[!] ${domain} is invalid :(`);
                    invalid.push(domain);
                }
                if (res.status === 'VALID') {
                    console.log(`${domain} is valid`);
                }
            }
        }
        //  This will cause API throttling
        // const promises = domains.map(async (domain) => {
        //     const res = await emailValidation(`test@${domain}`);
        //     if (res && res.status !== 'VALID') {
        //         invalid.push(domain);
        //     }
        // });
        // await Promise.all(promises);
        console.log(JSON.stringify(invalid, null, 2));
    })();
};

main();