Максим

const zip = (arr1, arr2) => arr1.reduce(
  (acc, head, i) => (acc.push({ ...arr2[i], head }), acc),
  []
);

zip(mass1, mass2) 
/* [
  { t1: "aa", p1: "lot", head: "zn1" },
  { t1: "ab", p1: "kot", head: "zn2" },
  { t1: "ac", p1: "mot", head: "zn3" },
] */

let mass1 = ["zn1", "zn2", "zn3"]
let mass2 = [
  {t1: "aa", p1: "lot"},
  {t1: "ab", p1: "kot"},
  {t1: "ac", p1: "mot"}
]

let mass3 = []

for (let i = 0; i < mass1.length; i++) {
    mass3.push(
        Object.assign(mass2[i], {head: mass1[i]})
    )
}

[...new Map(arr.map((item) => [item["key"], item])).values()]

const uniqueIds = [];
arr.filter(element => {
  const isDuplicate = uniqueIds.includes(element.key);

  if (!isDuplicate) {
    uniqueIds.push(element.key);

    return true;
  }

  return false;
});

Object.values(
  arr.reduce( (c, e) => {
    if (!c[e.key]) c[e.key] = e;
    return c;
  }, {})
);

const unique = (arr, key) => {
   const keys = new Set();
   return arr.filter(el => !keys.has(el[key]) && keys.add(el[key]));
 };
unique(arr, 'key')

- let input = document.getElementsByClassName('form-control');
+ const input = document.querySelector('input.form-control');

const res = await fetch('https://jsonplaceholder.typicode.com/users');
const data = await res.json();
console.log(data)

.item{
display: flex;
  flex-direction:column;
  align-items:center;
  
}
span{
  margin-top: auto;
}

document.querySelector('.close').addEventListener('click', function(e){
  e.stopPropagation()
  document.querySelector('.result').insertAdjacentHTML('beforeend', '<div>Close</div>');
});

Object.fromEntries(Object.entries(obj).sort((a, b) => b[1] - a[1]))

Возможно есть аналоги на js или jquer

html, body {
  margin: 0;
  padding: 0;
}