const btn = document.querySelector('.btn');
btn.addEventListener('click', function() {
  this.textContent = 'Clicked';
});

for (var i = 0; i < 3; i++) {
  setTimeout(() => console.log(i), 0);
}

console.log(1 + "2" - 1);

div {
  width: 100px;
  padding: 20px;
  box-sizing: content-box;
}
/* Чему равна полная ширина элемента? */

console.log(1);
setTimeout(() => console.log(2), 0);
Promise.resolve().then(() => console.log(3));
console.log(4);

let count = 0;
const nums = [0, 1, 2, 3];

nums.forEach(num => {
  if (num) count += 1;
});

console.log(count);

.parent {
  display: flex;
  height: 200px;
}
.child {
  height: 50%;
  flex-grow: 1;
}
/* Какая высота будет у .child? */

const bird = {
  size: 'small'
};

const mouse = {
  name: 'Mickey',
  small: true
};

console.log(mouse[bird.size]);

const user = { name: "Alice" };
Object.freeze(user);
user.name = "Bob";
console.log(user.name);

div {
  display: flex;
  justify-content: center;
}
/* Как будут выровнены элементы? */

const a = [1, 2, 3];
const b = a.map(num => {
  if (num > 1) return num;
});
console.log(b);