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script.js
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script.js
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// 1
function getExtremeElements(array) {
const firstEl = array[0];
const lastEl = array[array.length - 1];
array.length = 0;
array.push(firstEl, lastEl);
return array;
}
// 2
function getExtremeElements(array) {
const firstEl = array.slice(0, 1)
const lastEl = array.slice(-1)
return firstEl.concat(lastEl);
}
// 3
function getExtremeElements(array) {
const indexToLast = array.length - 2;
array.splice(1, indexToLast)
return array;
}
// 4
function getExtremeElements(array) {
const firstEl = array[0];
const lastEl = array[array.length - 1];
return [firstEl, lastEl];
}
getExtremeElements(['Earth', 'Mars', 'Venus', 'Mars', 'Yupiter'])
//
function calculateEngravingPrice(message, pricePerWord) {
const newArr = message.split(' ')
const engravingPrice = pricePerWord * newArr.length;
return engravingPrice;
}
calculateEngravingPrice('Web-development is creative work', 20)
//
function slugify(title) {
const slug = title.toLowerCase().split(' ').join('-');
return slug;
}
slugify('How to become a JUNIOR developer for TWO WEEKS')
// 1
function makeArray(firstArray, secondArray, maxLength) {
const newArr = firstArray.concat(secondArray);
if (newArr.length > maxLength) {
return newArr.slice(0, maxLength);
}
return newArr;
}
// 2
function makeArray(arr1, arr2, max) {
return arr1.concat(arr2).slice(0, max);
// return [...arr1, ...arr2].slice(0, max);
}
makeArray(['Mango'], ['Ajax', 'Chelsea', 'Poly', 'Houston'], 3);
// 1
function findLongestWord(string) {
return string.split(' ').reduce(function (longest, word) {
return word.length > longest.length ? word : longest;
}, '')
}
// 2
function findLongestWord(string) {
const newArr = string.split(' ');
let longestWord = '';
for (word of newArr) {
if (word.length > longestWord.length) {
longestWord = word;
}
}
return longestWord;
}
findLongestWord("The quick brown fox jumped over the lazy dog");
//
function checkFruit(fruit) {
const fruits = ["apple", "plum", "pear", "orange"];
for (fr of fruits) {
return fruits.includes(fruit);
}
}
checkFruit("mandarin");
checkFruit("plum");
// 1
function getCommonElements(array1, array2) {
let newArr = array2.concat(array1);
const uniqArr = newArr.filter((item, index) => { index !== newArr.indexOf(item) });
return uniqArr;
}
// 2
function getCommonElements(array1, array2) {
let newArr = [];
for (const num of array1) {
if (array2.includes(num)) {
newArr.push(num);
};
};
return newArr;
}
getCommonElements([1, 2, 3], [2, 1, 17, 19])
getCommonElements([10, 20, 30, 40], [4, 30, 17, 10, 40])
//
function getEvenNumbers(start, end) {
const newArr = [];
for (let i = start; i <= end; i += 1) {
if (i % 2 === 0) {
newArr.push(i);
}
}
return newArr;
}
getEvenNumbers(6, 12)
getEvenNumbers(7, 7)
getEvenNumbers(8, 8)
//
function includes(array, value) {
let bool;
for (const elem of array) {
if (elem === value) {
bool = true;
break;
} else {
bool = false;
}
}
return bool;
}
includes([1, 2, 3, 4, 5], 17);
includes(['Earth', 'Mars', 'Venus', 'Jupiter', 'Saturn'], 'Jupiter');
includes([1, 2, 3, 4, 5], 3);
//
function getCommonElements(arr) {
const duplicates = [];
for (let i = 0; i < arr.length; i += 1) {
if (arr.includes(arr[i], i + 1)) {
duplicates.push(arr[i]);
}
}
return duplicates;
}
getCommonElements([1, 2, 3, 2, 17, 1, 17, 2, 19]);
// Codewars
function addLength(str) {
const newArr = str.split(' ');
for (let i = 0; i < newArr.length; i += 1) {
newArr[i] += ' ' + newArr[i].length;
}
return newArr;
}
addLength("apple ban"); // ["apple 5", "ban 3"]
addLength("you will win") // ["you 3", "will 4", "win 3"]
// Codewars
function pipeFix(numbers) {
const lastEl = numbers[numbers.length - 1];
const firstEl = numbers[0];
const newArr = [];
for (let i = firstEl; i <= lastEl; i += 1) {
newArr.push(i)
}
return newArr
}
pipeFix([1, 3, 5, 6, 7, 8]);
// Codewars
function triangular(n) {
if (n <= 0) {
return 0;
}
return n * (n + 1) / 2
// let sum = 0;
// for (let i = 0; i <= n; i += 1) {
// sum += i;
// }
// return sum;
}
triangular(4); // 10
triangular(2); // 3
triangular(-10); // 0
// Codewars
function isIsogram(str) {
return new Set(str.toLowerCase()).size === str.length;
// return str.charAt(0) !== str.charAt(0).toLowerCase() || !str ? true : false; // Wrong variant, didn't got the instructions :)
}
isIsogram("Dermatoglyphics"); // true
isIsogram("isogram"); // true
isIsogram("aba"); // false
isIsogram("moOse"); // false
isIsogram("isIsogram"); //false
isIsogram(""); // true
//
function calculatePrice(arr) {
return arr.reduce((acc, next) => acc + next, 0)
}
calculatePrice([12, 85, 37, 4]);
//
function countProps(object) {
let propCount = 0;
const keys = Object.keys(object)
for (const key of keys) {
if (object.hasOwnProperty(key)) {
propCount += 1;
}
}
return propCount;
}
countProps({ mail: 'poly@mail.com', isOnline: true, score: 500 });
//
const products = [
{ name: "Radar", price: 1300, quantity: 4 },
{ name: "Scanner", price: 2700, quantity: 3 },
{ name: "Droid", price: 400, quantity: 7 },
{ name: "Grip", price: 1200, quantity: 9 },
];
function calculateTotalPrice(productName) {
for (const product of products) {
if (product.name === productName) {
return product.price * product.quantity;
}
}
return 0;
}
calculateTotalPrice("Radar");
calculateTotalPrice("Droid");
calculateTotalPrice("Blaster");
//
function findMatches([...numbers], ...args) {
const matches = [];
for (const num of numbers) {
if (args.includes(num)) {
matches.push(num);
}
}
// for (let i = 0; i < numbers.length; i += 1) {
// if (args.includes(numbers[i])) {
// matches.push(numbers[i]);
// }
// }
return matches;
}
findMatches([1, 2, 3, 4, 5], 1, 8, 2, 7);
findMatches([4, 89, 17, 36, 2], 8, 17, 89, 27, 2);
//
const bookShelf = {
books: ["The last kingdom", "Haze", "The guardian of dreams"],
updateBook(oldName, newName) {
const { books } = bookShelf;
const indexOfOldBook = books.indexOf(oldName)
books.splice(indexOfOldBook, 1, newName)
// 2
// books[indexOfOldBook] = newName
return books;
},
};
bookShelf.updateBook('Haze', 'Dungeon chronicles');
bookShelf.updateBook('The last kingdom', 'Dune');
//
const atTheOldToad = {
potions: [
{ name: "Speed potion", price: 460 },
{ name: "Dragon breath", price: 780 },
{ name: "Stone skin", price: 520 },
],
getPotions() {
return this.potions
},
addPotion(newPotion) {
for (const potion of this.potions) {
if (potion.name === newPotion.name) {
return `Error! Potion ${newPotion.name} is already in your inventory!`;
}
}
this.potions.push(newPotion);
},
removePotion(potionName) {
const { potions } = this;
for (let i = 0; i < potions.length; i += 1) {
if (potions[i].name === potionName) {
potions.splice(i, 1)
}
}
return `Potion ${potionName} is not in inventory!`;
},
updatePotionName(oldName, newName) {
const { potions } = this;
for (let i = 0; i < potions.length; i += 1) {
if (potions[i].name === oldName) {
return potions[i].name = newName;
}
}
return `Potion ${oldName} is not in inventory!`;
},
};
atTheOldToad.updatePotionName('Speed potion', 'Some potion');
//
const array = [
{
name: "Moore Hensley",
email: "moorehensley@indexia.com",
eyeColor: "blue",
friends: ["Sharron Pace"],
isActive: false,
balance: 2811,
gender: "male",
age: 37
},
{
name: "Sharlene Bush",
email: "sharlenebush@tubesys.com",
eyeColor: "blue",
friends: ["Briana Decker", "Sharron Pace"],
isActive: true,
balance: 3821,
gender: "female",
age: 34
},
{
name: "Ross Vazquez",
email: "rossvazquez@xinware.com",
eyeColor: "green",
friends: ["Marilyn Mcintosh", "Padilla Garrison", "Naomi Buckner"],
isActive: false,
balance: 3793,
gender: "male",
age: 24
},
{
name: "Elma Head",
email: "elmahead@omatom.com",
eyeColor: "green",
friends: ["Goldie Gentry", "Aisha Tran"],
isActive: true,
balance: 2278,
gender: "female",
age: 21
},
{
name: "Carey Barr",
email: "careybarr@nurali.com",
eyeColor: "blue",
friends: ["Jordan Sampson", "Eddie Strong"],
isActive: true,
balance: 3951,
gender: "male",
age: 27
},
{
name: "Blackburn Dotson",
email: "blackburndotson@furnigeer.com",
eyeColor: "brown",
friends: ["Jacklyn Lucas", "Linda Chapman"],
isActive: false,
balance: 1498,
gender: "male",
age: 38
},
{
name: "Sheree Anthony",
email: "shereeanthony@kog.com",
eyeColor: "brown",
friends: ["Goldie Gentry", "Briana Decker"],
isActive: true,
balance: 2764,
gender: "female",
age: 39
}
]
const getUsersWithFriend = (users, friendName) => {
return users.filter(user => user.friends.includes(friendName));
};
getUsersWithFriend(array, 'Briana Decker');
getUsersWithFriend(array, 'Adrian Cross');
//
const profile = {
name: "Alex",
age: 23,
stats: {
followers: 200,
likes: 23000,
},
location: "USA",
getProperty({ name, age, stats: { followers, likes }, location }) {
return followers, likes;
},
};
profile.getProperty(profile);
//
const usersArr = [
{
name: "Moore Hensley",
email: "moorehensley@indexia.com",
eyeColor: "blue",
friends: ["Sharron Pace"],
isActive: false,
balance: 2811,
skills: ["ipsum", "lorem"],
gender: "male",
age: 37,
},
{
name: "Sharlene Bush",
email: "sharlenebush@tubesys.com",
eyeColor: "blue",
friends: ["Briana Decker", "Sharron Pace"],
isActive: true,
balance: 3821,
skills: ["tempor", "mollit", "commodo", "veniam", "laborum"],
gender: "female",
age: 34,
},
{
name: "Ross Vazquez",
email: "rossvazquez@xinware.com",
eyeColor: "green",
friends: ["Marilyn Mcintosh", "Padilla Garrison", "Naomi Buckner"],
isActive: false,
balance: 3793,
skills: ["nulla", "anim", "proident", "ipsum", "elit"],
gender: "male",
age: 24,
},
{
name: "Elma Head",
email: "elmahead@omatom.com",
eyeColor: "green",
friends: ["Goldie Gentry", "Aisha Tran"],
isActive: true,
balance: 2278,
skills: ["adipisicing", "irure", "velit"],
gender: "female",
age: 21,
},
{
name: "Carey Barr",
email: "careybarr@nurali.com",
eyeColor: "blue",
friends: ["Jordan Sampson", "Eddie Strong"],
isActive: true,
balance: 3951,
skills: ["ex", "culpa", "nostrud"],
gender: "male",
age: 27,
},
{
name: "Blackburn Dotson",
email: "blackburndotson@furnigeer.com",
eyeColor: "brown",
friends: ["Jacklyn Lucas", "Linda Chapman"],
isActive: false,
balance: 1498,
skills: ["non", "amet", "ipsum"],
gender: "male",
age: 38,
},
{
name: "Sheree Anthony",
email: "shereeanthony@kog.com",
eyeColor: "brown",
friends: ["Goldie Gentry", "Briana Decker"],
isActive: true,
balance: 2764,
skills: ["lorem", "veniam", "culpa"],
gender: "female",
age: 39,
},
];
const getUserNames = users => {
return users.map(user => user.name);
};
getUserNames(usersArr);
//
const books = [
{
title: "The Last Kingdom",
author: "Bernard Cornwell",
genres: ["adventure", "history"],
},
{
title: "Beside Still Waters",
author: "Robert Sheckley",
genres: ["fiction", "mysticism"],
},
{
title: "Redder Than Blood",
author: "Tanith Lee",
genres: ["horror", "mysticism", "adventure"],
},
];
const allGenres = books.flatMap(book => book.genres);
const uniqueGenres = allGenres.filter((genre, index, arr) => arr.indexOf(genre) === index);
//
const books2 = [
{
title: "The Last Kingdom",
author: "Bernard Cornwell",
rating: 8.38,
},
{
title: "Beside Still Waters",
author: "Robert Sheckley",
rating: 8.51,
},
{
title: "The Dream of a Ridiculous Man",
author: "Fyodor Dostoevsky",
rating: 7.75,
},
{ title: "Redder Than Blood", author: "Tanith Lee", rating: 7.94 },
{ title: "Enemy of God", author: "Bernard Cornwell", rating: 8.67 },
];
const MIN_RATING = 8;
const AUTHOR = "Bernard Cornwell";
const topRatedBooks = books2.filter(({ rating }) => rating > MIN_RATING);
const booksByAuthor = books2.filter(({ author }) => author === AUTHOR);
//
const friends = [
{
name: "Moore Hensley",
email: "moorehensley@indexia.com",
eyeColor: "blue",
friends: ["Sharron Pace"],
isActive: false,
balance: 2811,
gender: "male",
age: 37
},
{
name: "Sharlene Bush",
email: "sharlenebush@tubesys.com",
eyeColor: "blue",
friends: ["Briana Decker", "Sharron Pace"],
isActive: true,
balance: 3821,
gender: "female",
age: 34
},
{
name: "Ross Vazquez",
email: "rossvazquez@xinware.com",
eyeColor: "green",
friends: ["Marilyn Mcintosh", "Padilla Garrison", "Naomi Buckner"],
isActive: false,
balance: 3793,
gender: "male",
age: 24
},
{
name: "Elma Head",
email: "elmahead@omatom.com",
eyeColor: "green",
friends: ["Goldie Gentry", "Aisha Tran"],
isActive: true,
balance: 2278,
gender: "female",
age: 21
},
{
name: "Carey Barr",
email: "careybarr@nurali.com",
eyeColor: "blue",
friends: ["Jordan Sampson", "Eddie Strong"],
isActive: true,
balance: 3951,
gender: "male",
age: 27
},
{
name: "Blackburn Dotson",
email: "blackburndotson@furnigeer.com",
eyeColor: "brown",
friends: ["Jacklyn Lucas", "Linda Chapman"],
isActive: false,
balance: 1498,
gender: "male",
age: 38
},
{
name: "Sheree Anthony",
email: "shereeanthony@kog.com",
eyeColor: "brown",
friends: ["Goldie Gentry", "Briana Decker"],
isActive: true,
balance: 2764,
gender: "female",
age: 39
}
]
const getFriends = (users) => {
return users.flatMap(user => user.friends).filter((friend, index, arr) => arr.indexOf(friend) === index);
};
getFriends(friends);
//
const getActiveUsers = (users) => {
return users.filter(({ isActive }) => isActive);
};
getActiveUsers(friends);
//
const players = [
{ name: "Mango", playtime: 1270, gamesPlayed: 4 },
{ name: "Poly", playtime: 469, gamesPlayed: 2 },
{ name: "Ajax", playtime: 690, gamesPlayed: 3 },
{ name: "Kiwi", playtime: 241, gamesPlayed: 1 },
];
const totalAveragePlaytimePerGame = players.reduce((acc, player) => acc + player.playtime / player.gamesPlayed, 0);
//
const arrOfFriends = [
{
name: "Moore Hensley",
email: "moorehensley@indexia.com",
eyeColor: "blue",
friends: ["Sharron Pace"],
isActive: false,
balance: 2811,
gender: "male"
},
{
name: "Sharlene Bush",
email: "sharlenebush@tubesys.com",
eyeColor: "blue",
friends: ["Briana Decker", "Sharron Pace"],
isActive: true,
balance: 3821,
gender: "female"
},
{
name: "Ross Vazquez",
email: "rossvazquez@xinware.com",
eyeColor: "green",
friends: ["Marilyn Mcintosh", "Padilla Garrison", "Naomi Buckner"],
isActive: false,
balance: 3793,
gender: "male"
},
{
name: "Elma Head",
email: "elmahead@omatom.com",
eyeColor: "green",
friends: ["Goldie Gentry", "Aisha Tran"],
isActive: true,
balance: 2278,
gender: "female"
},
{
name: "Carey Barr",
email: "careybarr@nurali.com",
eyeColor: "blue",
friends: ["Jordan Sampson", "Eddie Strong"],
isActive: true,
balance: 3951,
gender: "male"
},
{
name: "Blackburn Dotson",
email: "blackburndotson@furnigeer.com",
eyeColor: "brown",
friends: ["Jacklyn Lucas", "Linda Chapman"],
isActive: false,
balance: 1498,
gender: "male"
},
{
name: "Sheree Anthony",
email: "shereeanthony@kog.com",
eyeColor: "brown",
friends: ["Goldie Gentry", "Briana Decker"],
isActive: true,
balance: 2764,
gender: "female"
}
]
const getTotalFriendCount = users => {
return users.reduce((length, user) => length + user.friends.length, 0);
};
getTotalFriendCount(arrOfFriends);
//
const releaseDates = [2016, 1967, 2008, 1984, 1973, 2012, 1997];
const ascendingReleaseDates = [...releaseDates].sort((a, b) => `'a: ', ${a} + ' ', 'b: ', ${b}`);
//
const books4 = [
{
title: "The Last Kingdom",
author: "Bernard Cornwell",
rating: 8.38,
},
{
title: "Beside Still Waters",
author: "Robert Sheckley",
rating: 8.51,
},
{
title: "The Dream of a Ridiculous Man",
author: "Fyodor Dostoevsky",
rating: 7.75,
},
{ title: "Redder Than Blood", author: "Tanith Lee", rating: 7.94 },
{ title: "Enemy of God", author: "Bernard Cornwell", rating: 8.67 },
];
const sortedByAuthorName = [...books4].sort((author2, author1) => author2.author.localeCompare(author1));
const sortedByReversedAuthorName = [...books4].sort((author2, author1) => author1.author.localeCompare(author2));
const sortedByAscendingRating = [...books4].sort((author2, author1) => author1.rating - author2.rating);
const sortedByDescentingRating = [...books4].sort((author2, author1) => author2.rating - author1.rating);
//
const sortByAscendingBalance = users => {
return [...users].sort((a, b) => a.balance - b.balance)
};
//
const sortByDescendingFriendCount = users => {
return [...users].sort((user2, user1) => user1.friends.length - user2.friends.length)
};
//
const sortByName = users => {
return [...users].sort((user2, user1) => user2.name.localeCompare(user1.name));
};
//
const books5 = [
{
title: "The Last Kingdom",
author: "Bernard Cornwell",
rating: 8.38,
},
{
title: "Beside Still Waters",
author: "Robert Sheckley",
rating: 8.51,
},
{
title: "The Dream of a Ridiculous Man",
author: "Fyodor Dostoevsky",
rating: 7.75,
},
{ title: "Redder Than Blood", author: "Tanith Lee", rating: 7.94 },
{
title: "The Dreams in the Witch House",
author: "Howard Lovecraft",
rating: 8.67,
},
];
const MIN_BOOK_RATING = 8;
const names = books5.filter(book => book.rating > MIN_BOOK_RATING).map(user => user.author).sort((user2, user1) => user2.localeCompare(user1));
//
const getNamesSortedByFriendCount = users => {
return [...users].sort((user2, user1) => user2.friends.length - user1.friends.length).map(user => user.name);
};
//
const getSortedFriends = users => {
return [...users]
.flatMap(user => user.friends)
.filter((friend, index, arr) => arr.indexOf(friend) === index)
.sort((friend2, friend1) => friend2.localeCompare(friend1));
};
//
const someUsers = [
{
name: "Moore Hensley",
email: "moorehensley@indexia.com",
eyeColor: "blue",
friends: ["Sharron Pace"],
isActive: false,
balance: 2811,
gender: "male"
},
{
name: "Sharlene Bush",
email: "sharlenebush@tubesys.com",
eyeColor: "blue",
friends: ["Briana Decker", "Sharron Pace"],
isActive: true,
balance: 3821,
gender: "female"
},
{
name: "Ross Vazquez",
email: "rossvazquez@xinware.com",
eyeColor: "green",
friends: ["Marilyn Mcintosh", "Padilla Garrison", "Naomi Buckner"],
isActive: false,
balance: 3793,
gender: "male"
},
{
name: "Elma Head",
email: "elmahead@omatom.com",
eyeColor: "green",
friends: ["Goldie Gentry", "Aisha Tran"],
isActive: true,
balance: 2278,
gender: "female"
},
{
name: "Carey Barr",
email: "careybarr@nurali.com",
eyeColor: "blue",
friends: ["Jordan Sampson", "Eddie Strong", "Adrian Cross"],
isActive: true,
balance: 3951,
gender: "male"
},
{
name: "Blackburn Dotson",
email: "blackburndotson@furnigeer.com",
eyeColor: "brown",
friends: ["Jacklyn Lucas", "Linda Chapman", "Adrian Cross", "Solomon Fokes"],
isActive: false,
balance: 1498,
gender: "male"
},
{
name: "Sheree Anthony",
email: "shereeanthony@kog.com",
eyeColor: "brown",
friends: ["Goldie Gentry", "Briana Decker"],
isActive: true,
balance: 2764,
gender: "female"
}
]
const getTotalBalanceByGender = (users, gender) => {
return [...users].filter(user => user.gender === gender).reduce((total, currentUser) => total + currentUser.balance, 0);
};
getTotalBalanceByGender(someUsers, 'male');
//
class Storage {
constructor(items) {
this.items = items;
}
getItems() {
return this.items;
}
addItem(newItem) {
this.items.push(newItem);
}
removeItem(itemToRemove) {
const indexToRemove = this.items.indexOf(itemToRemove);
return this.items.splice(indexToRemove, 1);
}
}
const storage = new Storage(["Nanitoids", "Prolonger", "Antigravitator"]);
storage.getItems(); // ["Nanitoids", "Prolonger", "Antigravitator"]
storage.addItem("Droid");
storage.getItems(); // ["Nanitoids", "Prolonger", "Antigravitator", "Droid"]
storage.removeItem("Prolonger");
storage.getItems(); // ["Nanitoids", "Antigravitator", "Droid"]
//
class StringBuilder {
constructor(initialValue) {
this.value = initialValue;
}
getValue() {
return this.value;
}
padStart(str) {
this.value = str + this.value;
}
padEnd(str) {
this.value += str;
}
padBoth(str) {
this.value = str + this.value + str;
// this.padStart(str)
// this.padEnd(str)
}
}
const builder = new StringBuilder(".");
builder.getValue(); // "."
builder.padStart("^");
builder.getValue(); // "^."
builder.padEnd("^");
builder.getValue(); // "^.^"
builder.padBoth("=");
builder.getValue(); // "=^.^="
//
class Car {
MAX_PRICE = 50000;
#price;
constructor({ price }) {
this.#price = price;
}
get price() {
return this.#price;
}
set price(newPrice) {
if (newPrice < this.MAX_PRICE) {
this.#price = newPrice;
}
return;
}
}
const audi = new Car({ price: 35000 });
// console.log(audi.price); // 35000
audi.price = 49000;
// console.log(audi.price); // 49000
audi.price = 51000;
// console.log(audi.price); // 49000
//
class User {
email;
constructor(email) {
this.email = email;
}
get email() {
return this.email;
}
/**
* @param {string} newEmail
*/
set email(newEmail) {
if (typeof newEmail === 'string' && newEmail !== '') this.email = newEmail;
}
}
class Admin extends User {
constructor({ email, accessLevel }) {
super(email);
this.accessLevel = accessLevel;
}