index.js

const fs = require("fs");
const axios = require("axios");

let dns = [];

function trimSlash(input) {
    return input.endsWith('/') ? input.slice(0, -1) : input;
}

function findRDAPUrl(domain) {
    if (!domain) {
        throw new Error("You must enter a domain");
    }
    const tld = domain.split(".")[domain.split(".").length -1];
    if (!tld || tld === "") {
        throw new Error("Error parsing domain");
    }

    if (!dns.length) {
        const dnsFile = fs.readFileSync(`${__dirname}/tlds.json`, "utf-8");
        dns = JSON.parse(dnsFile);
    }

    const foundTld = dns.find(i => i[0].find(j => j === tld));
    if (!foundTld) {
        throw new Error(`Unable to find tld ${tld}`);
    }
    const rdapUrl = trimSlash(foundTld[1][0]);
    return rdapUrl;
}

async function whois(domain) {
    return new Promise(async (resolve, reject) => {
        try {
            let strippedDomain = domain.replace(/^(?:https?:\/\/)?(?:www\.)?/i, "");
            strippedDomain = trimSlash(strippedDomain);
            const rdapUrl = findRDAPUrl(strippedDomain);
            const requestUrl = `${rdapUrl}/domain/${strippedDomain}`;
            const response = await axios.get(requestUrl);
            const { data } = response;
            if (!data || typeof data !== "object") {
                throw new Error(`Error making WHOIS request for domain: ${domain}`);
            }
            resolve(data);
        } catch (error) {
            reject(error);
        }
    });
    
}

module.exports = whois;