rtviner

findLongestSubstring Solution
function findLongestSubstring(str) {
  let longest = 0;
  let seen = {};
  let start = 0;
 
  for (let i = 0; i < str.length; i++) {
    let char = str[i];
    if (seen[char]) {
      start = Math.max(start, seen[char]);

rtviner

function countdown (minutes) {
    
    for (let seconds = minutes * 60 ; seconds >= 0; seconds--) {
        setTimeout(() => tick(seconds), 1000);
    }

    function tick (seconds) {
        let secondsView = ((seconds%60) >= 10) ? seconds%60 : `0${seconds%60}`;
        console.log(`${Math.floor(seconds/60)||"00"}:${secondsView||"00"}`);
    }

rtviner

let outputValue = document.getElementById('output');
let numbers = document.querySelectorAll('.num-btn');
let decimal = document.getElementById('dec-btn')
let operators = document.querySelectorAll('.op-btn');
let equals = document.getElementById('equal-btn');
let clear = document.getElementById('clear');
let inputValue = [];

function add(num1, num2) {
	return num1 + num2;