zhibirc

const buttons = [...document.getElementsByClassName('button')];
let focusedButtonIndex = 0;

buttons[focusedButtonIndex].focus();

window.addEventListener('keydown', event => {
  if ( buttons.some(button => button === event.target) ) {
    if ( event.code === 'ArrowDown' || event.code === 'ArrowUp' ) {
      buttons[focusedButtonIndex ^= 1].focus();
    }

zhibirc

/**
 * Implement Circular/Ring Buffer basic behaviour.
 *
 * @version 1
 *
 * @example
 * const buffer = new CircularBuffer(3);
 *
 * buffer.list(); // []
 * buffer.push('URL 1');

zhibirc

/**
 * Basic password generator.
 * Alphabet: digits, English letters in both cases, and special characters.
 *
 * @param {number[]} range - list of two numeric values "from" and "to" which are UTF code points
 * @param {number} length - password length, small values aren't recommended for security reasons
 *
 * @return {Generator<string, void, *>}
 */
function* generatePassword ( range = [33, 126], length = 20 ) {

zhibirc

/** @see {@link https://en.wikipedia.org/wiki/Digit_sum} */
const dsum = n => n < 10 ? n : n % 10 + dsum(n / 10 | 0);

/** @see {@link https://encyclopediaofmath.org/wiki/Factorial} */
const fact = n => n ? n * fact(n - 1) : 1;

/** @see {@link https://encyclopediaofmath.org/wiki/Greatest_common_divisor} */
const gcd = (a, b) => b ? gcd(b, a % b) : a;

/** @see {@link https://encyclopediaofmath.org/wiki/Power|Fast algorithm} */

zhibirc

/* Aim:
"function <function name>() {
    [native code]
}"
*/

function protect ( fn ) {
  fn.toString = fn.toLocaleString = fn.toSource = function () {
      return 'function ' + fn.name + '() { [native code] }';
  };

zhibirc

// basic implementation
function protect ( fn ) {
  fn.toString = fn.toLocaleString = fn.toSource = function () {
      return 'function ' + fn.name + '() { [native code] }';
  };
}

// but indirect call still available, so fix it
var protect = (function () {
    // function can be reassign with different name, so use functions itself instead of string names