ilanl

function reduce(arr, reduceCallback, initialValue) {
  if (!Array.isArray(arr) || !arr.length || typeof reduceCallback !== 'function') 
  {
    return [];
  } else {
    let hasInitialValue = initialValue !== undefined;
    let value = hasInitialValue ? initialValue : arr[0];
    for (let i = hasInitialValue ? 0 : 1, len = arr.length; i < len; i++) {
      value = reduceCallback(value, arr[i], i, arr); 
    }

ilanl

function filter(arr, filterCallback) {
  if (!Array.isArray(arr) || !arr.length || typeof filterCallback !== 'function') 
  {
    return [];
  } else {
    let result = [];
    for (let i = 0, len = arr.length; i < len; i++) {
      if (filterCallback(arr[i], i, arr)) {
        result.push(arr[i]);
      }

ilanl

function map(arr, mapCallback) {
  if (!Array.isArray(arr) || !arr.length || typeof mapCallback !== 'function') { 
    return [];
  } else {
    let result = [];
    for (let i = 0, len = arr.length; i < len; i++) {
      result.push(mapCallback(arr[i], i, arr));
    }
    return result;
  }

ilanl

const arr = [ ...Array(100).keys() ].map( i => i+1).sort((a, b) => a-b);
console.log(...arr)
var results = []
while (arr.length > 0) {
  results.push(arr.shift())
  results.push(arr.pop())
}
console.log(...results)

ilanl

const delay = t => new Promise(resolve => setTimeout(resolve, t));

ilanl

```
t1	MEMORY	t2
		0	
read	0		0
inc			1
write		1	1
read			1
inc			2
write		2	2
read			2

ilanl

// Constructor

function Car( model, year, miles ) {
 
  this.model = model;
  this.year = year;
  this.miles = miles;
 
  this.toString = function () {
    return this.model + " has done " + this.miles + " miles";

ilanl

function reducer(acc, currentValue, currentIndex, arr) {
  acc[currentValue] = (acc[currentValue]+1) || 1;
  return acc;
}

function countWords(arrOfWords) {
  return arrOfWords.reduce(reducer, {});
}

ilanl

class MyMap extends Map {
  constructor() {
    super();
    this.counter = 0;
    this.all_value = null;
  }

  set(key, value) {
    if (value) {
      super.set(key, { ts: this.counter++, v: value });

ilanl

const exp = '10+2*5*3+6';
const result = exp.split('+').reduce((added, e) => added += (e.split('*').reduce((multiplied, k) => multiplied *= parseInt(k), 1) ), 0 );
console.log(result);