ancyrweb

const elements = [1, [2], 3, [4, 5], [6]];
const nextElements = elements.flat(); // [1, 2, 3, 4, 5, 6]

ancyrweb

function flatten(array) {
  return array.reduce((previousValue, currentValue) => {
    if (Array.isArray(currentValue)) {
      // current value is an array, merge values and return the result
      return [...previousValue, ...currentValue];
    }

    // current value is not an array, just add it to the end of the accumulation
    return [...previousValue, currentValue];
  }, []);

ancyrweb

const elements = [1, [2, [3, 4, [5], 6], [7, [8]]]];
const result = elements.flat(Infinity); // [1, 2, 3, 4, 5, 6, 7, 8]

ancyrweb

const elements = [1, 2, 4, 5];
const indexToInsert = 2; // we will append the element at index 2
const elementToInsert = 3; // we will insert the number "3"

const nextElements = [
  ...elements.slice(0, indexToInsert),
  elementToInsert,
  ...elements.slice(indexToInsert),
]; // [1, 2, 3, 4, 5]

ancyrweb

const elements = [1, 2, 4, 5];
const indexToInsert = 2; // we will append the element at index 2
const elementToInsert = 3; // we will insert the number "3"

const nextElements = elements.reduce((previousValue, currentValue, index) => {
  previousValue.push(currentValue); // 😱
  if (index === indexToInsert) {
    previousValue.push(elementToInsert); // 😱😱
  }
  return previousValue;

ancyrweb

const elements = [1, 6, 4, 5, 2, 3];
const byOrderAsc = (a, b) => a - b;
const nextElements = elements.slice().sort(byOrderAsc); // [1, 2, 3, 4, 5, 6]

ancyrweb

const elements = Array(10).fill().map((a, i) => i);
// [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

ancyrweb

const champions = [
  {
    name: "Darius",
    level: 7,
  },
  {
    name: "Katarina",
    level: 12,
  },
  {

ancyrweb

const champions = [
  {
    name: "Darius",
    level: 7,
  },
  {
    name: "Katarina",
    level: 4,
  },
  {

ancyrweb

const users = [
  {
    id: 1,
    username: "supercoder",
  },
  {
    id: 2,
    username: "xXxSniperElitexXx",
  },
  {