We have an array of arrays like this −const arr = [    ['foo', 'bar', 'hey', 'oi'],    ['foo', 'bar', 'hey'],    ['foo', 'bar', 'anything'],    ['bar', 'anything'] ]We are required to write a JavaScript function that takes in such array and returns an array that contains all the strings which appears in all the subarrays.Let's write the code for this functionExampleconst arr = [    ['foo', 'bar', 'hey', 'oi'],    ['foo', 'bar', 'hey'],    ['foo', 'bar', 'anything'],    ['bar', 'anything'] ] const commonArray = arr => {    return arr.reduce((acc, val, index) => {       return acc.filter(el => val.indexOf(el) !== -1);    }); }; console.log(commonArray(arr));OutputThe output in the console will be −['bar']

We are required to write a JavaScript function that takes in a number and returns its reversed number with converting it to an array or string.Let's write the code for this function −Exampleconst num = 234567; const reverseNumber = (num, res = 0) => {    if(num){       return reverseNumber(Math.floor(num / 10), (res*10)+(num % 10));    };    return res; }; console.log(reverseNumber(num)); console.log(reverseNumber(53536)); console.log(reverseNumber(76576));OutputThe output in the console will be −765432 63535 67567

We are required to write a JavaScript function that takes in an array of Numbers with positive as well as negative numbers and returns the maximum products of two numbers in one traversal.Let's write the code for this function −Exampleconst arr = [-1, -3, -4, 2, 0, -5]; const arr2 = [2, 3, 5, 7, -7, 5, 8, -5]; const produce = arr => arr.reduce((acc, val) => acc*val); const maximumProduct = (arr = []) => {    const [first] = arr;    if(!first){       return 0;    };    const creds = arr.reduce((acc, val) => {     ... Read More

We are required to write a JavaScript function that takes in an array of numbers and returns an array with all even numbers appearing on the left side of any odd number and all the odd numbers appearing on the right side of any even number.Therefore, let's write the code for this function −Exampleconst arr = [2, 6, 3, 7, 8, 3, 5, 4, 3, 6, 87, 23, 2, 23, 67, 4]; const isEven = num => num % 2 === 0; const sorter = (a, b) => {    if(isEven(a) && !isEven(b)){       return -1;    };    if(!isEven(a) && isEven(b)){       return 1;    };    return 0; }; arr.sort(sorter); console.log(arr);OutputThe output in the console will be −[    2, 6, 8, 4, 6, 2,    4, 3, 7, 3, 5, 3,    87, 23, 23, 67 ]

We are required to write a JavaScript function that accepts two strings and a number n. The function matches the two strings i.e., it checks if the two strings contains the same characters. The function should return true if both the strings contain the same character irrespective of their order or if they contain at most n different characters, otherwise the function should return false.Let's write the code for this function −Exampleconst str1 = 'first string'; const str2 = 'second string'; const wildcardMatching = (first, second, num) => {    let count = 0;    for(let i = 0; i ... Read More

We are required to write a JavaScript function that takes in two objects (possibly nested) and returns a new object with key value pair for the keys that were present in the first object but not in the secondLet's write the code for this function −Exampleconst obj1 = {    "firstName": "Raghav",    "lastName": "Raj",    "age": 43,    "address": "G-12 Kalkaji",    "email": "raghavraj1299@yahoo.com",    "salary": 90000 }; const obj2 = {    "lastName": "Raj",    "address": "G-12 Kalkaji",    "email": "raghavraj1299@yahoo.com",    "salary": 90000 }; const objectDifference = (first, second) => {    return Object.keys(first).reduce((acc, val) => { ... Read More

We are required to write a JavaScript function that takes in a string with repetitive characters and returns a new string in which all the same characters are exactly n characters away from each other. And the number should be smaller than the length of the array.For example −If the input string is: "accessories" And the number n is 3 Then, The return value should be: "secrsecisao"Note − There may be some other permutation to achieve the required output, the order is not important, we should stick to the logic and as long as we fulfil it our output is ... Read More

We have an array of arrays that contains the marks scored by some students in some subjects −const arr = [    ['Math', 'John', 100],    ['Math', 'Jake', 89],    ['Math', 'Amy', 93],    ['Science', 'Jake', 89],    ['Science', 'John', 89],    ['Science', 'Amy', 83],    ['English', 'John', 82],    ['English', 'Amy', 81],    ['English', 'Jake', 72] ];We are required to write a function that takes in this array and retuns an array of object, with one object for each subject and the details about the top scorer of that subject.Our output should look like −[    { "Subject": "Math", ... Read More

We are required to write a JavaScript function that takes in a string and a number n as two arguments (the number should be such that it exactly divides the length of string). And we have to return an array of n strings of equal length.For example −If the string is "helloo" and the number is 3 Our output should be: ["ho", "eo", "ll"]Here, each substring exactly contains (length of array/n) characters. And each substring is formed by taking corresponding first and last letters of the string alternativelyLet's write the code for this function −Exampleconst str = 'helloo'; const splitEqual ... Read More

We are required to write a JavaScript function that takes in an array of Numbers with some positive and negative values. We are required to determine whether there exists a subarray in the original array whose net sum is 0 or not.Our function should return a boolean on this basis.ApproachThe approach here is simple. We iterate over the array using a for loop, calculate the cumulative sum up to that particular element. And if any point the cumulative becomes 0 or attains a value it has previously attained, then there exists a subarray with sum 0. Otherwise there exists no ... Read More