Bulk IP Whois parser for Nodejs

bulk_whois_parser.js

const LineByLineReader = require('line-by-line');

//
// Read bulk whois data from file
//
const reader = new LineByLineReader('whois_dump.txt');

let whoisdata = {
    'organization': [],
    'inetnum': [],
    'inet6num': [],
    'person': [],
    'as-set': [],
    'as-block': [],
    'aut-num': [],
    'domain': [],
};
let data = [];

reader.on('line', line => {

    if (line.length < 2 && data.length > 2) {
        let item = parse(data.join('\n'));
        let type = Object.keys(item)[0];
        if (whoisdata[type]) {
            whoisdata[type].push(item)
        }
        data = [];
    }

    if (line.length > 1 && line.substring(0) !== '#') {
        data.push(line);
    }
});

reader.on('end', () => {
    console.log(JSON.stringify(whoisdata, null, 2));
});


const parse = (data) => {
    let whoisObj = {};
    let str = data.toString();
    let lines = str.split(/(\r?\n)/g);

    let lastKey = '';

    for (let i in lines) {
        let line = lines[i];
        if (line && line.trim() && line.indexOf('%') != 0 && line.indexOf('#') != 0) {

            let dataValuePair = [lastKey, line.trim()];
            if (line.includes(': ') && line.substring(0, 1) !== ' ') {
                dataValuePair = line.split(":");
            }

            if (dataValuePair.length >= 2) {
                let name = dataValuePair[0].trim()
                    , value = dataValuePair.slice(1).join(":").trim();
                lastKey = name;
                if (whoisObj[name] instanceof Array) {
                    whoisObj[name].push(value);
                } else {
                    if (whoisObj[name] && whoisObj[name] != value) {
                        //if there is several values with same name organizing them as array
                        let tmp = whoisObj[name];
                        whoisObj[name] = [];
                        whoisObj[name].push(tmp);
                        whoisObj[name].push(value);
                    }
                    else
                        whoisObj[name] = value;
                }
            }
            else if (Array.isArray(whoisObj[lastKey])) {
                whoisObj[lastKey].push(line.trim())
            }
        }
    }
    return whoisObj;
};