We are required to write a JavaScript function that takes in two numbers specifying a range. Our function should return a random prime number that falls in that rangeExampleThe code for this will be −const range = [100, 1000]; const getPrimes = (min, max) => {    const result = Array(max + 1)    .fill(0)    .map((_, i) => i);    for (let i = 2; i {    return Math.floor(Math.random() * (max − min + 1) + min); }; const getRandomPrime = ([min, max]) => {    const primes = getPrimes(min, max);    return primes[getRandomNum(0, primes.length − 1)]; }; console.log(getRandomPrime(range));OutputAnd the output in the console will be −311Output is likely to differ in each run.

Suppose we have an array of true/false represented by 't'/'f' which we retrieved from some database like this −const arr = ['f', 't', 'f', 't', 't', 't', 'f', 'f', 't', 't', 't', 't', 't', 't', 'f', 't'];We are required to write a JavaScript function that takes in one such array. Our function should count the consecutive appearances of those 't' that are sandwiched between two 'f's and return an array of that count.Therefore, for the above array, the output should look like −const output = [1, 3, 6, 1];ExampleThe code for this will be −const arr = ['f', 't', 'f', ... Read More

We are required to write a JavaScript function that takes in two strings, say str1 and str2. The function should then count and return the number of times str2 appears in str1'For example −count('this is a string', 'is') should return 2;ExampleThe code for this will be −const str1 = 'this is a string'; const str2 = 'is'; const countOccurrences = (str1, str2, allowOverlapping = true) => {    str1 += "";    str2 += "";    if (str2.length = 0) {          ++n;          pos += step;       } else break;    }    return n; }; console.log(countOccurrences(str1, str2));OutputAnd the output in the console will be −2

Suppose we have an array of arrays that contains the marks of some students in some subjects like this −const arr = [ ["English", 52], ["Hindi", 154], ["Hindi", 241], ["Spanish", 10], ["French", 65], ["German", 98], ["Russian", 10] ];We are required to write a JavaScript function that takes in one such array and returns an object of objects.The return object should contain an object for each unique subject, and that object should contain information like the number of appearances of that language, sum of total marks and the average.ExampleThe code for this will be −const arr = [    ["English", 52], ... Read More

In this tutorial, we will learn how to do a case-insensitive string comparison of strings in JavaScript. Case in-sensitive simply means the word or string should mean the same even if they are written in lower or upper case. In this kind of case in-sensitive comparison is observed in the google search bar, wherein if the user type “tUtoriAlsPOint” or “Tutorialspoint” the results are the same, similarly it is used in search bar too. There are 4 ways to do this, toUpperCase() toLowerCase() localeCompare() RegExp() Using the toUpperCase() Method When we use the toUpperCase() method on a string, ... Read More

Cartesian ProductThe Cartesian product of two sets (arrays) A and B, denoted A × B, is the set (array) of all ordered pairs (a, b) where a is in A and b is in B.In simpler terms, a cartesian product of two arrays is a permutation of all possible arrays of two elements whose first element belongs to the first array and the second element belongs to the second array.For example − If the two arrays are −const arr1 = [1, 2, 3]; const arr2 = [4, 5];Then their cartesian product will be −const product = [[1, 4], [1, 5], ... Read More

Suppose, we have an array of Strings that contains month-year combined strings like this −const arr = ["2009-feb", "2009-jan", "2010-mar", "2010-jan", "2011-jul", "2011-sep", "2011-jan", "2012-jan", "2012-dec", "2012-feb", "2013-may", "2013-jul", "2013-jun", "2014-jan", "2014-dec", "2014-may", "2015-may", "2015-jan", "2015-jun", "2016-jan", "2016-dec"];We are required to write a JavaScript function that takes in one such array and sorts these dates in oldest to latest order.ExampleThe code for this will be −const arr = ["2009-feb", "2009-jan", "2010-mar", "2010-jan", "2011-jul", "2011-sep", "2011-jan", "2012-jan", "2012-dec", "2012-feb", "2013-may", "2013-jul", "2013-jun", "2014-jan", "2014-dec", "2014-may", "2015-may", "2015-jan", "2015-jun", "2016-jan", "2016-dec"]; const sorter = (a, b) => {    const getDate = ... Read More

We are required to write a JavaScript function that takes in a number as one and the only argument. The function should then return a randomly generated string of the length specified by the argument.The character set to be used for the string generation should only contain uppercase and lowercase alphabets (no whitespaces, punctuations or numerals).ExampleThe code for this will be −const num = 13; const randomString = (len = 1) => {    const charSet =    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';    let randomString = '';    for (let i = 0; i < len; i++) {       let randomPoz ... Read More

We are required to write a JavaScript function that takes in an array of literals as the first argument and a string as the second argument. Our function should return the count of the number of times that string (provided by second argument) appears anywhere in the array.ExampleThe code for this will be −const arr = ["word", "a word", "another word"]; const query = "word"; const findAll = (arr, query) => {    let count = 0;    count = arr.filter(el => {       return el.indexOf(query) != -1;    }).length;    return count; }; console.log(findAll(arr, query));OutputAnd the output in the console will be −3

Let's say we have such an array −const arr = [A, A, B, B, C, C, D, E];We are required to create an algorithm so that it will find all the combinations that add up to the whole array, where none of the elements are repeated.Example combinations −[A, B, C, D, E] [A, B, C] [A, B, C, D] [A, B, C, E] [A, B, C] [A, B, C] [D, E]Explanation[A, B, C] [A, B, C] [D, E] and [A, B, C] [D, E] [A, B, C] are the same combinations. Also, the ordering with the subsets doesn't matter as ... Read More