0xD34F

const arr = Object
  .entries(obj)
  .reduce((acc, [ k, values ]) => (
    values.forEach((v, i) => (acc[i] ??= {})[k] = v),
    acc
  ), []);

const keys = Object.keys(obj);
const arr = obj[keys[0]]?.map((_, i) => {
  return Object.fromEntries(keys.map(k => [ k, obj[k][i] ]));
}) ?? [];

const duplicates = arr.filter((n, i, a) => a.filter(m => m[0] === n[0]).length > 1);

const duplicates = Object
  .values(arr.reduce((acc, n) => ((acc[n[0]] ??= []).push(n), acc), {}))
  .flatMap(n => n.length > 1 ? n : []);

const duplicates = Array
  .from(arr
    .reduce((acc, n) => (acc.get(n[0]).push(n), acc), new Map(arr.map(n => [ n[0], [] ])))
    .values())
  .reduce((acc, n) => (n.length > 1 && acc.push(...n), acc), []);

const duplicates = arr.filter(function(n) {
  return this.get(n[0]);
}, arr.reduce((acc, [ n ]) => acc.set(n, acc.has(n)), new Map));

document.querySelector('.btn--start').addEventListener('click', filterItems);
document.querySelector('select').addEventListener('change', e => e.target.value === 'all' && filterItems());

function filterItems() {
  const val = document.querySelector('select').value;

  document.querySelectorAll('.item').forEach(n => {
    n.style.display = [ n.dataset.elem, 'all' ].includes(val)
      ? 'block'
      : 'none';
  });
}

Object.fromEntries(new URLSearchParams(arr.join('&')))

arr.reduce((acc, n) => (
  n = n.split('='),
  acc[n[0]] = n[1],
  acc
), {})

Object.assign(...arr.map(n => n.match(/[^=]+/g)).map(([ k, v ]) => ({ [k]: v })))

eval(`({${arr.map(n => `"${n.replace('=', '":"')}"`)}})`)

<div data-value="69"></div>
<div data-value="187"></div>
<div data-value="666"></div>

function animateValue(elem) {
  return new Promise(resolve => {
    const endValue = +elem.dataset.value;
    let currValue = 0;

    const interval = setInterval(() => {
      if (++currValue === endValue) {
        clearInterval(interval);
        resolve();
      }

      elem.innerText = currValue;
    }, 20);
  });
}


Array
  .from(document.querySelectorAll('[data-value]'))
  .reduce((p, c) => p.then(() => animateValue(c)), Promise.resolve());

function({ 'xxx-yyy': xxxYyy }) {

}

def chunked(arr, chunk_size):
  return [ arr[i:i + chunk_size] for i in range(0, len(arr), chunk_size) ]


print(chunked([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ], 4)) # [[0, 1, 2, 3], [4, 5, 6, 7], [8, 9]]

The useRef() Hook isn’t just for DOM refs. The “ref” object is a generic container whose current property is mutable and can hold any value, similar to an instance property on a class.

const result = arr.reduce((acc, n, i) => (
  (i & 1) || acc.push(0),
  acc[~-acc.length] += n,
  acc
), []);

function chunked(data, chunkSize) {
  return Array.prototype.reduce.call(
    data,
    (acc, n, i) => ((acc[i / chunkSize | 0] ??= []).push(n), acc),
    []
  );
}

function sum(data, val = n => n) {
  const getVal = val instanceof Function ? val : n => n[val];
  return Array.prototype.reduce.call(
    data,
    (acc, n) => acc + getVal(n),
    0
  );
}


const result = chunked(arr, 2).map(n => sum(n));

.active {
  &::after {
    content: "hello, world!!";
  }
}

<a class="tabs-select__button" data-text="hello, world!!">
<a class="tabs-select__button" data-text="fuck the world">

.active {
  &::after {
    content: attr(data-text);
  }
}

const flatArr = arr.flatMap(n => Array.isArray(n.DOP) ? n.DOP : []);
// или
const flatArr = Array.prototype.concat.apply([], arr.map(n => n.DOP ?? []));
// или
const flatArr = arr.reduce((acc, n) => (n.DOP && acc.push(...n.DOP), acc), []);

const unique = Object.values(Object.fromEntries(flatArr.map(n => [ n.NAME, n ])));
// или
const unique = flatArr.filter(function({ NAME: n }) {
  return !(this[n] = this.hasOwnProperty(n));
}, {});
// или
const unique = flatArr.filter((n, i, a) => n === a.find(m => m.NAME === n.NAME));

function formatDate(str) {
  const d = new Date(str.replace('_', ' 1, '));
  d.setMonth(d.getMonth() - 1);
  return d.toLocaleDateString('en-US', {
    month: 'short',
    year: 'numeric',
  }).replace(' ', '_');
}

formatDate('Feb_2021') // "Jan_2021"
formatDate('Jan_2000') // "Dec_1999"

this.setState(({ items }) => ({
  items: items.map((n, i) => ({ ...n, id: i })),
}));

state = {
  items: this.props.items.map((n, i) => ({ ...n, id: i })),
}

computed: {
  grouped() {
    return this.arr.reduce((acc, n) => ((acc[n.group] ??= []).push(n), acc), {});
  },
},

<v-expansion-panels>
  <v-expansion-panel v-for="(items, groupName) in grouped">
    <v-expansion-panel-header>{{ groupName }}</v-expansion-panel-header>
    <v-expansion-panel-content>
      <div v-for="n in items">{{ n.name }}</div>
    </v-expansion-panel-content>
  </v-expansion-panel>
</v-expansion-panels>

str.match(/(?<=\. ).+(?= \(%\))/)[0]

// или

str.replace(/^.*?\. | \(%\).*$/g, '')

// или

str.split('. ').pop().split(' (%)').shift()