Javascript Articles - Page 267 of 534

Suppose, we have an array like this −const arr = [    [1, 2, 3, 4],    [12, 13, 14, 5],    [11, 16, 15, 6],    [10, 9, 8, 7] ];The array is bound to be a square matrix.We are required to write a JavaScript function that takes in this array and constructs a new array by taking elements and spiraling in until it converges to center. A snail trail spiraling around the outside of the matrix and inwards.Therefore, the output for the above array should be −const output = [1, 2, 3, 4, 5, 6, 7, 8, 9, ... Read More

We are required to write a JavaScript function that takes in a string and turns it into a Mexican Wave i.e. resembling string produced by successive captial letters in every word −For example −If the string is −const str = 'edabit';Then the output should be the following i.e. successive single capital letter −const output = ["Edabit", "eDabit", "edAbit", "edaBit", "edabIt", "edabiT"];ExampleFollowing is the code −const str = 'edabit'; const replaceAt = function(index, char){    let a = this.split("");    a[index] = char;    return a.join(""); }; String.prototype.replaceAt = replaceAt; const createEdibet = word => {    let array = word.split('') ... Read More

Suppose, we have an array of objects like this −const homes = [    {        "h_id": "3",        "city": "Dallas",        "state": "TX",        "zip": "75201",        "price": "162500"    }, {        "h_id": "4",        "city": "Bevery Hills",        "state": "CA",        "zip": "90210",        "price": "319250"    }, {        "h_id": "5",        "city": "New York",        "state": "NY",        "zip": "00010",        "price": "962500"    } ... Read More

Suppose we have an object like this −const obj = {    name: "Ramesh",    age: 34,    occupation: "HR Manager",    address: "Tilak Nagar, New Delhi",    experience: 13 };We are required to write a JavaScript function on Objects that computes their size (i.e., the number of properties in it).ExampleFollowing is the code −const obj = {    name: "Ramesh",    age: 34,    occupation: "HR Manager",    address: "Tilak Nagar, New Delhi",    experience: 13 }; Object.prototype.size = function(obj) {    let size = 0, key;    for (key in obj) {       if (obj.hasOwnProperty(key)){          size++       };    };    return size; }; const size = Object.size(obj); console.log(size);This will produce the following output on console −5

Suppose, we have this dummy array that contains the login info of two of many users of a social networking platform −const array = [{    email: 'usman@gmail.com',    password: '123'  },  {    email: 'ali@gmail.com',    password: '123'  } ];We are required to write a JavaScript function that takes in an email string and a password string.The function should return a boolean based on the fact whether or not the user exists in the database.ExampleFollowing is the code −const array = [{    email: 'usman@gmail.com',    password: '123' }, {    email: 'ali@gmail.com',    password: '123' }]; const matchCredentials ... Read More

A nasty zombie virus is spreading out in the digital cities. We work at the digital CDC and our job is to look over the city maps and tell which areas are contaminated by the zombie virus so the digital army would know where to drop the bombs.They are the new kind of digital zombies which can travel only in vertical and horizontal directions and infect only numbers same as them.We'll be given a two-dimensional array with numbers in it.For some mysterious reason patient zero is always found in north west area of the city (element [0][0] of the matrix) ... Read More

Suppose, we have an array and objects like the following −const main = [    {name: "Karan", age: 34},    {name: "Aayush", age: 24},    {name: "Ameesh", age: 23},    {name: "Joy", age: 33},    {name: "Siddarth", age: 43},    {name: "Nakul", age: 31},    {name: "Anmol", age: 21}, ]; const names = ["Karan", "Joy", "Siddarth", "Ameesh"];We are required to write a JavaScript function that takes in two such arrays and filters the first array in place to contain only those objects whose name property is included in the second array.ExampleFollowing is the code −const main = [ {name: "Karan", ... Read More

We are required to declare a function, let’s say insertAllPositions, which takes two arguments −an element, x, and an array, arr. Functions must return an array of arrays, with each array corresponding to arr with x inserted in a possible position.That is, if arr is the length N, then the result is an array with N + 1 arrays −For example, the result of insertAllPositions(10, [1, 2, 3]) should be −const output = [    [10, 1, 2, 3],    [1, 10, 2, 3],    [1, 2, 10, 3],    [1, 2, 3, 10] ];We are required to write this ... Read More

Suppose we have two arrays of literals like these −const options = ['A', 'B', 'C', 'D']; const values = [true, false, false, false];We are required to write a JavaScript function that creates and returns a new Array of Objects from these two arrays, like this −const response = [    {opt: 'A', val: true},    {opt: 'B', val: false},    {opt: 'C', val: false},    {opt: 'D', val: false}, ];ExampleFollowing is the code −const options = ['A', 'B', 'C', 'D']; const values = [true, false, false, false]; const mapArrays = (options, values) => {    const res = [];   ... Read More

We are required to write a JavaScript function that generates an array of exactly five unique random numbers. The condition is that all the numbers have to be in the range [0, 9] and the first number cannot be 0.ExampleFollowing is the code −const fiveRandoms = () => {    const arr = []    while (arr.length < 5) {       const random = Math.floor(Math.random() * 10);       if (arr.indexOf(random) > -1){          continue;       };       if(!arr.length && !random){          continue;       }       arr[arr.length] = random;    }    return arr; }; console.log(fiveRandoms());OutputThis will produce the following output in console −[ 9, 0, 8, 5, 4 ]