0xD34F

new MutationObserver((mutations, observer) => {
  if (mutations[0].target.classList.contains('интересующий-вас-класс')) {
    observer.disconnect();
    typed.start();
  }
}).observe(элементНаличиеКлассаУКоторогоНадоОтследить, { attributes: true });

const getTheNearestLocation = (locations, [ x, y ]) =>
  locations.reduce((nearest, n) => {
    const d = ((n[1][0] - x) ** 2 + (n[1][1] - y) ** 2) ** 0.5;
    return nearest[1] < d ? nearest : [ n, d ];
  }, [ null, Infinity ])[0];

const parent = document.querySelector('ul');
const id = 'item';

const elems = Array.from(parent.children);
const index = elems.findIndex(n => n.id === id);
const result = index === -1 ? elems : elems.slice(0, index);

// или

const result = [...parent.querySelectorAll(`:not(#${id}, #${id} ~ *)`)];

// или

const result = [];
for (
  let el = parent.firstElementChild;
  el && el.id !== id;
  el = el.nextElementSibling
) {
  result.push(el);
}

const makeCensored = (str, words, replacement = '***') =>
  str
    .split(' ')
    .map(n => words.includes(n) ? replacement : n)
    .join(' ');

const obj = Object.fromEntries(await Promise.all(ids.map(async n => [ n, await loadPosts(n) ])));

const group = (arr, idKey, valKey) =>
  Object.values(arr.reduce((acc, { [idKey]: id, [valKey]: val }) => (
    (acc[id] ??= { [idKey]: id, [valKey]: [] })[valKey].push(val),
    acc
  ), {}));


const result = group(data, 'id', 'color');

str.split(';').pop()
// или
str.replace(/.*;/, '')
// или
str.match(/;(.*)/)[1]
// или
/[^;]+$/.exec(str).shift()
// или
str.slice(str.lastIndexOf(';') + 1)
// или
[...str].reduce((acc, n) => n === ';' ? '' : acc + n)
// или
Array.from(str).filter((n, i, a) => !a.includes(';', i)).join('')

const newArr = arr.map(function(n) {
  return [ ...n, ...Array(this - n.length).fill('') ];
}, Math.max(...arr.map(n => n.length)));

const max = arr.reduce((max, { length: n }) => max > n ? max : n, 0);
arr.forEach(n => n.push(...Array(max - n.length).fill('')));

parseInt('1!!!') // 1
+'1!!!' // NaN


parseInt('') // NaN
+'' // 0


parseInt('3.14159') // 3
+'3.14159' // 3.14159


parseInt('0b1000101') // 0
+'0b1000101' // 69


parseInt('0o273') // 0
+'0o273' // 187


parseInt({ valueOf: () => 666 }) // NaN
+({ valueOf: () => 666 }) // 666


parseInt('1000000000', 2) // 512
+'1000000000' // 1000000000


parseInt('99', 8) // NaN
+'99' // 99


parseInt('DEAD', 16) // 57005
+'DEAD' // NaN

function update(target, source, key, props) {
  source.forEach(function(n) {
    const item = this[n[key]];
    item && props.forEach(m => item[m] = n[m]);
  }, Object.fromEntries(target.map(n => [ n[key], n ])));
}


update(directions, [ { раз объект }, { два объект }, ... ], 'id', [ 'color' ]);

document.addEventListener('click', e => {
  const btn = e.target.closest('.more-btn');
  for (const n of document.querySelectorAll('.more-btn')) {
    n.classList.toggle('active', n === btn && !n.classList.contains('active'));
  }

  // или

  document.querySelectorAll('.more-btn').forEach(function(n) {
    n.classList[n === this ? 'toggle' : 'remove']('active');
  }, e.target.closest('.more-btn'));
});

function weightedRandom(arr, key = () => 1) {
  const val = key instanceof Function ? key : n => n[key];
  const max = arr.reduce((acc, n) => acc + val(n), 0);

  return () => {
    let rand = Math.random() * max;
    return arr.find(n => (rand -= val(n)) < 0);
  };
}


const getRandomPhotosArray = weightedRandom([
  [ 9,  truePhotos ],
  [ 1, funnyPhotos ],
], 0);

function getPhoto() {
  const photos = getRandomPhotosArray()[1];
  return photos[Math.random() * photos.length | 0];
}

new ApexCharts(..., {
  ...
  tooltip: {
    ...
    y: {
      title: {
        formatter: (seriesName, seriesData) => ...,
      },
      formatter: (value, seriesData) => ...,
    },
  },
});

const getNestedData = arr =>
  Array.isArray(arr)
    ? arr.flatMap(n => [ n, ...getNestedData(n.children) ])
    : [];

for (const n of getNestedData(DATA)) {
  console.log(n);
}

function createTreeFromArray(arr, key, parentKey) {
  const tree = Object.fromEntries(arr.map(n => [ n[key], { ...n } ]));

  return Object.fromEntries(Object.entries(tree).filter(([ , n ]) => {
    return !(tree[n[parentKey]] && ((tree[n[parentKey]].children ??= {})[n[key]] = n));
  }));
}


const tree = createTreeFromArray(arr, 'uid', 'parentUID');

const teamNamesObj = Object.fromEntries(teamNames.map(n => [ n.id, n.name ]));
const eplWithNames = epl.map(n => ({ ...n, team_name: teamNamesObj[n.team_id] }));

epl.forEach(function(n) {
  n.team_name = this[n.team_id];
}, teamNames.reduce((acc, n) => (acc[n.id] = n.name, acc), {}));

arr.reduce((acc, n) => acc + (n ** 2) * !(n & 1), 0)

const countWithKey = (arr, key) => arr.filter(n => key in n).length;

console.log(countWithKey(arr, 'ключ'));

const sum = (data, val = n => n) =>
  Array.prototype.reduce.call(
    data,
    (acc, n) => acc + val(n),
    0
  );

console.log(sum(arr, obj => obj.hasOwnProperty('ключ')));

const cart = [
  { price: 100, count: 5 },
  { price:  10, count: 6 },
  { price:   1, count: 7 },
];

const total = sum(cart, item => item.price * item.count); // 567

const likes = sum(document.querySelectorAll('.btn_like .btn__counter'), n => +n.innerText);

function Counter(data, key = n => n) {
  const counted = new Map;

  for (const n of data) {
    const k = key(n);
    counted.set(k, (counted.get(k) ?? 0) + 1);
  }

  return k => counted.get(k) ?? 0;
}

const keyExists = Counter(arr, obj => Object.hasOwn(obj, 'ключ'));
console.log(keyExists(true)); // смотрим, у скольких элементов массива ключ есть
console.log(keyExists(false)); // и у скольких нет

const str = 'hello, world!!';

const chars = Counter(str);
console.log(chars('h')); // 1
console.log(chars('!')); // 2
console.log(chars('x')); // 0

const persons = [
  { name: 'Вася', birthday: new Date('1999-05-22') },
  { name: 'Маша', birthday: new Date('2004-03-06') },
  { name: 'Катя', birthday: new Date('1976-05-15') },
  { name: 'Петя', birthday: new Date('1987-04-18') },
  { name: 'Коля', birthday: new Date('2000-01-01') },
  { name: 'Дима', birthday: new Date('2003-05-09') },
  { name: 'Миша', birthday: new Date('1996-02-29') },
  { name: 'Таня', birthday: new Date('1981-03-12') },
  { name: 'Олег', birthday: new Date('1992-08-24') },
];

const birthMonths = Counter(
  persons,
  ({ birthday }) => birthday.toLocaleString('ru-RU', { month: 'long' })
);
console.log(birthMonths('май')); // в мае родилось три человека
console.log(birthMonths('март')); // в марте два
console.log(birthMonths('октябрь')); // а в октябре никто

function* naturalNumbers(n) {
  for (let i = 1; i <= n; i++) {
    yield i;
  }
}

const numLengths = Counter(naturalNumbers(100), num => `${num}`.length);
console.log(numLengths(2)); // среди первых ста натуральных чисел - девяносто двухзначных
console.log(numLengths(3)); // и одно трёхзначное
console.log(numLengths(0)); // число из нуля знаков? - конечно же нет таких

function objToString(val, tabSize = 2, depth = 0, noIndent = false) {
  const indent = ' '.repeat(tabSize * depth);

  return (noIndent ? '' : indent) + (
    val instanceof Array
      ? `[\n${val.map(n => objToString(n, tabSize, depth + 1)).join(',\n')}\n${indent}]`
      : val instanceof Object
        ? `{\n${Object
            .entries(val)
            .map(n => n.map((m, i) => objToString(m, tabSize, depth + 1, i)).join(': '))
            .join(',\n')}\n${indent}}`
        : typeof val === 'string'
          ? `"${val}"`
          : val
  );
}


console.log(objToString({
  numbers: [ 69, 187, 666 ],
  strings: [ 'hello, world!!', 'fuck the world', 'fuck everything' ],
  falsy_values: [ 0, '', NaN, false, null, undefined ],
  object: { xxx: true, yyy: Infinity, zzz: { '!&$': [ [ [ -1 ] ] ] } }
}));