const longestPalindrome = (s) => {
    if(s.length === 1) return s
    
    const odd = longestOddPalindrome(s)
    const even = longestEvenPalindrome(s)
    
    
    if(odd.length >= even.length) return odd
    if(even.length > odd.length) return even
};

const longestOddPalindrome = (s) => {    
    let longest = 0
    let longestSubStr = ""
    
    for(let i = 1; i < s.length; i++) {
        
        let currentLongest = 1
        let currentLongestSubStr = ""
        let left = i - 1
        let right = i + 1
        
        while(left >= 0 && right < s.length) {
            const leftLetter = s[left]
            const rightLetter = s[right]

            left--
            right++

            if(leftLetter === rightLetter) {
                currentLongest += 2
                currentLongestSubStr = s.slice(left+1, right)
            } else break
        }
        
                        
        if(currentLongest > longest) {
            if(currentLongestSubStr) longestSubStr = currentLongestSubStr 
            else longestSubStr = s[i]
            longest = currentLongest
        }
    }
    
    return longestSubStr
}

const longestEvenPalindrome = (s) => {    
    let longest = 0
    let longestSubStr = ""
    
    for(let i = 0; i < s.length - 1; i++) {
        if(s[i] !== s[i+1]) continue;
        
        let currentLongest = 2
        let currentLongestSubStr = ""
        let left = i - 1
        let right = i + 2
        
        while(left >= 0 && right < s.length) {
            const leftLetter = s[left]
            const rightLetter = s[right]

            left--
            right++
            
            if(leftLetter === rightLetter) {
                currentLongest += 2
                currentLongestSubStr = s.slice(left+1, right)
            } else break
        }
                
                
        if(currentLongest > longest) {
            if(currentLongestSubStr) longestSubStr = currentLongestSubStr
            else longestSubStr = s[i] + s[i+1]
    
            longest = currentLongest
        }
    }
    
    return longestSubStr
}
console.log(longestPalindrome("babad"))

"use strict";
const nodemailer = require("nodemailer");

// async..await is not allowed in global scope, must use a wrapper
async function main() {
  // Generate test SMTP service account from ethereal.email
  // Only needed if you don't have a real mail account for testing
  let testAccount = await nodemailer.createTestAccount();

  // create reusable transporter object using the default SMTP transport
  let transporter = nodemailer.createTransport({
    host: "smtp.ethereal.email",
    port: 587,
    secure: false, // true for 465, false for other ports
    auth: {
      user: testAccount.user, // generated ethereal user
      pass: testAccount.pass, // generated ethereal password
    },
  });

  // send mail with defined transport object
  let info = await transporter.sendMail({
    from: '"Fred Foo 👻" <[email protected]>', // sender address
    to: "[email protected], [email protected]", // list of receivers
    subject: "Hello ✔", // Subject line
    text: "Hello world?", // plain text body
    html: "<b>Hello world?</b>", // html body
  });

  console.log("Message sent: %s", info.messageId);
  // Message sent: <[email protected]>

  // Preview only available when sending through an Ethereal account
  console.log("Preview URL: %s", nodemailer.getTestMessageUrl(info));
  // Preview URL: https://ethereal.email/message/WaQKMgKddxQDoou...
}

main().catch(console.error);

const formatDuration = ms => {
  if (ms < 0) ms = -ms;
  const time = {
    day: Math.floor(ms / 86400000),
    hour: Math.floor(ms / 3600000) % 24,
    minute: Math.floor(ms / 60000) % 60,
    second: Math.floor(ms / 1000) % 60,
    millisecond: Math.floor(ms) % 1000
  };
  return Object.entries(time)
    .filter(val => val[1] !== 0)
    .map(([key, val]) => `${val} ${key}${val !== 1 ? 's' : ''}`)
    .join(', ');
};

formatDuration(1001); // '1 second, 1 millisecond'
formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds'

const union = (...arr) => [...new Set(arr.flat())];

// Example
union([1, 2], [2, 3], [3]);     // [1, 2, 3]

class Timer{
	start(){
		this.startTime = Date.now();
	}
	stop(){
		const dt = Date.now() - this.startTime;
		console.log(dt);
		return dt;
	}
	getExecTime(fun, asynchronous){
		return asynchronous ? this.getAsyncExecTime(fun) : this.getSyncExecTime(fun);
	}
	getSyncExecTime(fun){
		this.start();
		fun();
		return this.stop();
	}
	async getAsyncExecTime(fun){
		this.start();
		await fun();
		return this.stop();
	}
	static average(fun, numTimes, asynchronous = false){
		const times = [];
		const promises = [];
		let timer = new Timer();
		if(asynchronous){
			for(let i = 0; i < numTimes; i++){
				timer.getAsyncExecTime(fun);
			}
		}else{
			for(let i = 0; i < numTimes; i++){
				timer.getSyncExecTime(fun);
			}
		}
		return (times => times.reduce(((sum, acc) => sume + acc), 0) / times.length);
	}
	static async timeAsync(fun, numTimes){
		if(numTimes <= 1) return new Timer().getAsyncExecTime(fun);
		const promises = [];
		let timer = new Timer(true);
		for(let i = 0; i < numTimes; i++){
			promises.push(fun().catch((e)=>{}));
		}
		try{
			await Promise.all(promises).catch((e)=>{});
		}catch(e){
			//do absolutely nothing
		}
		return timer.stop();
	}
	constructor(start = false){
		if(start) this.start();
	}
}

class SequentialQueue{	//if you want it to go backwards, too bad
	next(){
		return this.i++;
	}
	constructor(start = 0){
		this.i = start;
	}
}
const que = new SequentialQueue(0);
for(let i = 0; i < 10; i++){
	console.log(que.next());
}