hzzzzl

filterData.map(c => {
  const [m, y] = c.validTill.split('/')
  const date = new Date(2000 + Number(y), m, 1, 23)  // придется переписать в 22м веке :(
  date.setDate(date.getDate() - 1)
  return {
    product: c.product,
    maskedNum: c.cardNum.slice(0, 4) + ' ****** ' + c.cardNum.slice(-4),
    validDate: date.toISOString()
  }
})

function click(e) {
  console.log(e.target.offsetWidth)
}

titles = ['title one', 'title two', 'title three']

searcheable.innerHTML = `<ul>
  ${ titles.map( t => `<li>${t}</li>` ).join('') }
</ul>`

/*
<ul>
 <li>title one</li><li>title two</li><li>title three</li>
</ul>
*/

var button = document.querySelectorAll('button');
button.addEventListener('click', function() { ... } )

const elems = document.querySelectorAll('p');
elems.length // 2

s = String(123456)
sum = 0
for(n in s) { 
  sum = sum + +n   // +n = Number(n)
}
// sum = 15

button.addEventListener('click', () => {
  if(something) {
    window.location = 'https://qna.habr.com/q/741299'
  }
})

при удалении возвращается обратно

let parent = el.closest('.promo');
let copyText = parent.querySelector('.promo-text')