0xD34F

const entries = Object.entries(obj);
const mustBeRemoved = v =>
  (v instanceof Object && !Object.keys(v).length) ||
  (!v && typeof v !== 'boolean');

const newObj = Object.fromEntries(entries.filter(n => !mustBeRemoved(n[1])));

entries.forEach(n => mustBeRemoved(n[1]) && delete obj[n[0]]);

const source = document.querySelector('.box1').children;
const target = document.querySelector('.box2');

target.firstElementChild.insertAdjacentHTML('afterend', Array
  .from(source, ({ innerText: n }) => `<p><a href="#${n}">${n}</a></p>`)
  .join('')
);

target.children[0].after(...Array.prototype.map.call(source, n => {
  const p = document.createElement('p');
  p.append(document.createElement('a'));
  p.lastChild.href = '#' + n.textContent;
  p.lastChild.text = n.textContent;
  return p;
}));

data('.nights')

data('.guests')

$('div').click(function(e) {
  if ($(e.target).is('span')) {
    return;
  }

  ...
});

const min = 0;
const max = 100;
const time = 5000;

(function step(val) {
  setTimeout(function() {
    document.querySelector('.block').innerText = val;
    if (val < max) {
      step(val + 1);
    }
  }, time / (max - min));
})(min);

$("#idModalEditUser").modal('show').find('.modal-body').text($(this).text());

const arr = [ '***', '+++' ];

const obj = {
  '!!!': [
    { id: 0, text: 'fjdklsfjklds' },
  ],
  '+++': [
    { id:  3, a: '111', b: '!!!' },
    { id:  9, a: '222', b: '???' },
    { id: 27, a: '333', b: ':::' },
    { id: 81, a: '444', b: '...' },
  ],
  '***': [
    { id:  69, text: 'hello, world!!' },
    { id: 187, text: 'fuck the world' },
    { id: 666, text: 'fuck everything' },
  ],
};

document.body.insertAdjacentHTML('beforeend', arr.map(n => {
  const columns = Object.keys(obj[n][0]);

  return `
    <h1>${n}</h1>
    <table>
      <thead>
        <tr>${columns.map(n => `
          <th>${n}</th>`).join('')}
        </tr>
      </thead>
      <tbody>${obj[n].map(row => `
        <tr>${columns.map(col => `
          <td>${row[col]}</td>`).join('')}
        </tr>`).join('')}
      </tbody>
    </table>`;
}).join(''));

document.body.append(...arr.flatMap(n => {
  const columns = Object.keys(obj[n][0]);
  const header = document.createElement('h1');
  const table = document.createElement('table');

  header.textContent = n;

  columns.forEach(function(col) {
    this.append(document.createElement('th'));
    this.lastChild.textContent = col;
  }, table.createTHead().insertRow());

  obj[n].forEach(function(row) {
    const tr = this.insertRow();
    columns.forEach(col => tr.insertCell().textContent = row[col]);
  }, table.createTBody());

  return [ header, table ];
}));

Логика такая, при клике на пункт списка, например "About" этот текст оказывался на месте текущего, а текущий в списке.

const item = event.target.closest('.dropdown-menu-item');
if (item) {
  const btn = item.closest('.dropdown').querySelector('.dropdown-toggle');
  [ btn.textContent, item.textContent ] = [ item.textContent, btn.textContent ];
}

JSON.stringify([...this.querySelectorAll('[name]')].map(n => ({
  [n.name]: n.type === 'checkbox' ? n.checked : n.value,
})))

const parseDate = str => new Date(str.split('/').reverse().join('-'));

all_orders.sort((a, b) => parseDate(a.order_date) - parseDate(b.order_date));

const sortedOrders = all_orders
  .map(n => [ n, parseDate(n.order_date) ])
  .sort((a, b) => a[1] - b[1])
  .map(n => n[0]);

str.replace(/(?<=.{2}).(?=.{2})/g, '*')

// или

str.replace(/^(.{2})(.+)(.{2})$/, (m, g1, g2, g3) => g1 + '*'.repeat(g2.length) + g3)

// или

Array.from(str, (n, i) => (i < 2 || i > str.length - 3) ? n : '*').join('')

[...Array(12)].map((n, i) => new Date(0, i).toLocaleString('en-US', { month: 'long' }))

Object.entries(arr.reduce((acc, n) => {
  const [ k, v ] = Object.entries(n)[0];
  (acc[k] = acc[k] || []).push(...v);
  return acc;
}, {})).map(n => Object.fromEntries([ n ]))

Пробовал ставить перед скобкой «\» не работает.

const createXML = obj => Object
  .entries(obj)
  .map(([ k, v ]) => `<ns1:${k}>${v instanceof Object ? createXML(v) : v}</ns1:${k}>`)
  .join('');

const createXML = (obj, tabSize = 2, depth = 0) => {
  const indent = ' '.repeat(tabSize * depth);
  return Object.entries(obj).map(([ k, v ]) =>
    indent +
    `<ns1:${k}>${
      v instanceof Object
        ? `\n${createXML(v, tabSize, depth + 1)}\n${indent}`
        : v
    }</ns1:${k}>`
  ).join('\n');
};

slide(e, ui) {
  $(this).find('.value').text(i => ui.values[i]);
},