e-mihaylin

const once = fn => ((...a) => {
  let executed = false;
  return (...a) => {
    if (!executed) {
      executed = true;
      return fn(...a);
    }
  };
})();

e-mihaylin

const gcd = (a, b) => a ? gcd(b % a, a) : b;
const lcm = (a, b) => a * b / gcd(a, b);

[1, 2, 3, 4, 5].reduce(lcm); // Returns 60

e-mihaylin

const add = n => {
  const f = x => add(n + x);
  f.valueOf = () => n;
  return f;
}

// Other Variants:
function add(n) {
  var f = function(x) { return add(n+x); };
  f.valueOf = function() { return n; };

e-mihaylin

const longestSlideDown = p => p.reduceRight((x, e) => e.map((v, i) => v + Math.max(x[i], x[i + 1])))[0];
// https://www.codewars.com/kata/551f23362ff852e2ab000037

e-mihaylin

const factorial = n => {
  if (!n) return '1'
  let i, next, carret;
  const result = n.toString().split``.reverse().map(Number);

  while (--n) {
    i = carret = 0;
    while ((next = result[i++]) !== undefined || carret) {
      carret += n * (next || 0);
      result[i - 1] = carret % 10;

e-mihaylin

const multiply = (a, b) => {
  const stack = [];
  a = a.split``.reverse();
  b = b.split``.reverse();
  
  for (let i = 0, la = a.length; i < la; i++) {
    for (let j = 0, lb = b.length; j < lb; j++) {
      const m = a[i] * b[j];
      const s = stack[i + j];
      stack[i + j] = s ? s + m : m;

e-mihaylin

const getPascalsTriangleRow = n => {
  const a = [];
  let x = 0;
  
  for (let i = 0; i < n; i++) {
    x = a.length - i;
    for (let j = 0; j < i + 1; j++)
      (j === 0 || j === i) ? a.push(1) : 
      a.push(a[x + j] + a[x + j - 1]);
  }

e-mihaylin

const count = n => Math.floor((ln(2 * Math.PI * n) / 2 + n * (ln(n) - 1)) / ln(10)) + 1;

const ln = x => Math.log(x) / Math.log(Math.E);

e-mihaylin

const calc = s => run(s.replace(/\s+/g, '').split``);

const run = s => {
  let result = term(s);
  while (peek(s) == '+' || peek(s) == '-') {
    if (get(s) == '+') result += term(s);
    else result -= term(s);
  }
  return result;
};

e-mihaylin

const justify = (s, length) => {
  s = s.replace(/\n/g, ' ')
  s = s.split` `;
  const res = [];
  let line = [];
  let words = 0;

  for (let i = 0; i < s.length; i++) {
    if (words + line.length - 1 + s[i].length < length) {
      line.push(s[i]);