yavgel85

// Sorts an array of numbers, using the selection sort algorithm.

// Use the spread operator (...) to clone the original array, arr.
// Use a for loop to iterate over elements in the array.
// Use Array.prototype.slice() and Array.prototype.reduce() to find the index of the minimum element in the subarray to the right of the current index and perform a swap, if necessary.

const selectionSort = arr => {
  const a = [...arr];
  for (let i = 0; i < a.length; i++) {
    const min = a

yavgel85

// Sorts an array of numbers, using the heapsort algorithm.

// Use recursion.
// Use the spread operator (...) to clone the original array, arr.
// Use closures to declare a variable, l, and a function heapify.
// Use a for loop and Math.floor() in combination with heapify to create a max heap from the array.
// Use a for loop to repeatedly narrow down the considered range, using heapify and swapping values as necessary in order to sort the cloned array.

const heapsort = arr => {
  const a = [...arr];

yavgel85

// Sorts an array of numbers, using the bucket sort algorithm.

// Use Math.min(), Math.max() and the spread operator (...) to find the minimum and maximum values of the given array.
// Use Array.from() and Math.floor() to create the appropriate number of buckets (empty arrays).
// Use Array.prototype.forEach() to populate each bucket with the appropriate elements from the array.
// Use Array.prototype.reduce(), the spread operator (...) and Array.prototype.sort() to sort each bucket and append it to the result.

const bucketSort = (arr, size = 5) => {
  const min = Math.min(...arr);
  const max = Math.max(...arr);

yavgel85

// Implementation of the Luhn Algorithm used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers etc.

// Use String.prototype.split(''), Array.prototype.reverse() and Array.prototype.map() in combination with parseInt() to obtain an array of digits.
// Use Array.prototype.splice(0, 1) to obtain the last digit.
// Use Array.prototype.reduce() to implement the Luhn Algorithm.
// Return true if sum is divisible by 10, false otherwise.

const luhnCheck = num => {
  let arr = (num + '')
    .split('')

yavgel85

// Finds all the indexes of a substring in a given string.

// Use Array.prototype.indexOf() to look for searchValue in str.
// Use yield to return the index if the value is found and update the index, i.
// Use a while loop that will terminate the generator as soon as the value returned from Array.prototype.indexOf() is -1.

const indexOfSubstrings = function* (str, searchValue) {
  let i = 0;
  while (true) {
    const r = str.indexOf(searchValue, i);

yavgel85

// Sorts an array of numbers, using the quicksort algorithm.

// Use recursion.
// Use the spread operator (...) to clone the original array, arr.
// If the length of the array is less than 2, return the cloned array.
// Use Math.floor() to calculate the index of the pivot element.
// Use Array.prototype.reduce() and Array.prototype.push() to split the array into two subarrays (elements smaller or equal to the pivot and elements greater than it), destructuring the result into two arrays.
// Recursively call quickSort() on the created subarrays.

const quickSort = arr => {

yavgel85

// Checks if the given string is an absolute URL.

// Use RegExp.prototype.test() to test if the string is an absolute URL.

const isAbsoluteURL = str => /^[a-z][a-z0-9+.-]*:/.test(str);

// Examples
isAbsoluteURL('https://google.com'); // true
isAbsoluteURL('ftp://www.myserver.net'); // true
isAbsoluteURL('/foo/bar'); // false

yavgel85

// Joins all given URL segments together, then normalizes the resulting URL.

// Use String.prototype.join('/') to combine URL segments.
// Use a series of String.prototype.replace() calls with various regexps to normalize the resulting URL (remove double slashes, add proper slashes for protocol, remove slashes before parameters, combine parameters with '&' and normalize first parameter delimiter).

const URLJoin = (...args) =>
  args
    .join('/')
    .replace(/[\/]+/g, '/')
    .replace(/^(.+):\//, '$1://')

yavgel85

// Gets the current URL without any parameters or fragment identifiers.

// Use String.prototype.replace() with an appropriate regular expression to remove everything after either '?' or '#', if found.

const getBaseURL = url => url.replace(/[?#].*$/, '');

// Examples
getBaseURL('http://url.com/page?name=Adam&surname=Smith'); // 'http://url.com/page'

yavgel85

// Creates an object containing the parameters of the current URL.

// Use String.prototype.match() with an appropriate regular expression to get all key-value pairs.
// Use Array.prototype.reduce() to map and combine them into a single object.
// Pass location.search as the argument to apply to the current url.

const getURLParameters = url =>
(url.match(/([^?=&]+)(=([^&]*))/g) || []).reduce(
  (a, v) => (
    (a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a