katepapineni

// What is the output?
console.log(typeof NaN);

console.log(typeof Number);

katepapineni

/* Promise.all() => Wait for multiple promises to resolve then proceed */
const promise1 = new Promise((resolve, reject) => {
    setTimeout(resolve, 1000, 'Resolving 1');
});
const promise2 = new Promise((resolve, reject) => {
    setTimeout(resolve, 2000, 'Resolving 2');
});
const promise3 = new Promise((resolve, reject) => {
    setTimeout(resolve, 1000, 'Resolving 3');
});

katepapineni

// What is the output?
const object = {};

console.log(!!Object.keys(object).length);

katepapineni

/* Optional Chaining (?.) in ES2020 */
const app = {
    frontend: {
        language: 'JavaScript',
        framework: 'ReactJS',
    },
    backend: {
        language: 'Python',
    },
    database: {

katepapineni

const dog1 = {
    name: 'Scout',
    age: 7,
};

const dog2 = {
    name: 'Snoopy',
    age: 3,
};

katepapineni

// What's the output?
console.log(NaN == NaN);

console.log(NaN === NaN);

console.log(Number.isNaN(NaN));

katepapineni

const curve = 5;
const students = [
    { name: 'Thor', score: 98 },
    { name: 'Wonder Woman', score: 92 },
    { name: 'Spiderman', score: 98 },
    { name: 'Captain America', score: 88 },
];

const scores = [...new Set(students.map(x => x.score + curve))];

katepapineni

const prices = { beer: 8, water: 1, latte: 4, 
                soda: 2, coffee: 3, wine: 12, };

function filter(prices) {
    return Object.keys(prices).reduce((acc, key) => {
        if (prices[key] % 2 === 0) {
            delete acc[key];
        }
        return acc;
    }, prices);

katepapineni

const url = 'https://www.myportfolio.com/experience/resume.pdf';

const result = (function(url) {
  return url.split('/').pop();
}(url));

// What's the output?
console.log(result);

katepapineni

const first = 200 && 300 && 100;

const second = 0 && 300 && 200;

const third = first || second && 0;

// What's the output?
console.log(first + second + third);