We are required to write a JavaScript function that takes in two arrays and merges the arrays taking elements alternatively from the arrays.For example −If the two arrays are −const arr1 = [4, 3, 2, 5, 6, 8, 9]; const arr2 = [2, 1, 6, 8, 9, 4, 3];Then the output should be −const output = [4, 2, 3, 1, 2, 6, 5, 8, 6, 9, 8, 4, 9, 3];ExampleFollowing is the code −const arr1 = [4, 3, 2, 5, 6, 8, 9]; const arr2 = [2, 1, 6, 8, 9, 4, 3]; const mergeAlernatively = (arr1, arr2) => {    const res = [];    for(let i = 0; i < arr1.length + arr2.length; i++){       if(i % 2 === 0){          res.push(arr1[i/2]);       }else{          res.push(arr2[(i-1)/2]);       };    };    return res; }; console.log(mergeAlernatively(arr1, arr2));OutputThis will produce the following output in console −[    4, 2, 3, 1, 2, 6,    5, 8, 6, 9, 8, 4,    9, 3 ]

Suppose, we have a comma separator string that contains some fruit names like this −const str = 'Banana, Banana, Pear, Orange, Apple, Melon, Grape, Apple, Banana, Grape, Melon, Grape, Melon, Apple, Grape, Banana, Orange, Melon, Orange, Banana, Banana, Orange, Pear, Grape, Orange, Orange, Apple, Apple, Banana';We are required to write a JavaScript function that takes in one such string and uses the for in loop to figure out the fruit name that appears for the greatest number of times in the string.The function should return the fruit string that appears for most number of times.ExampleFollowing is the code −const str ... Read More

Suppose, we have a special kind of string like this −const str ="Integer, 1 Float, 2.0Boolean, True Integer, 6Float, 3.66 Boolean, False";We are required to write a JavaScript function that converts the above string into the following array, using the String.prototype.split() method −const arr = [    {        "Integer":1,        "Float":2.0    },    {        "Boolean":true,        "Integer":6    },    {        "Float":3.66,        "Boolean":false    } ];We have to use the following rules for conversion −--- marks the end of an object --- ... Read More

We are required to write a JavaScript function that takes in an array of String/Number literals as the first argument and a String/Number as the second argument.If the variable taken as the second argument is not present in the array, we should return -1.Else if the number is present in the array, then we have to return the index of position the number would have occupied if the array were reversed. We have to do so without actually reversing the array.Then at last we have to attach this function to the Array.prototype object.For example −[45, 74, 34, 32, 23, 65].reversedIndexOf(23); ... Read More

Suppose we have an array that contains duplicate elements like this −const arr = [1,1,2,2,3,4,4,5];We are required to write a JavaScript function that takes in one such array and returns a new array. The array should only contain the elements that only appear once in the original array.ExampleFollowing is the code −const arr = [1,1,2,2,3,4,4,5]; const extractUnique = arr => {    const res = [];    for(let i = 0; i < arr.length; i++){       if(arr.lastIndexOf(arr[i]) !== arr.indexOf(arr[i])){          continue;       };       res.push(arr[i]);    };    return res; }; console.log(extractUnique(arr));OutputThis will produce the following output in console −[ 3, 5 ]

We are required to write a JavaScript function that takes in an array of numbers.The function should return the sum of all the prime numbers present in the array.Let’s say the following is our array −const arr = [43, 6, 6, 5, 54, 81, 71, 56, 8, 877, 4, 4];The function should sum the prime numbers i.e.43 + 5 + 71 + 877 = 996ExampleFollowing is the code −const arr = [43, 6, 6, 5, 54, 81, 71, 56, 8, 877, 4, 4]; const isPrime = n => {    if (n===1){       return false;    }else if(n ... Read More

We are required to write a JavaScript function that takes in a string that may contain some backward slashes. The function should return a new string with all the backward slashes replaced with forward slashes.Let’s say the following is our string −const str = 'Th/s str/ng /conta/ns some/ forward slas/hes';ExampleFollowing is the code −const str = 'Th/s str/ng /conta/ns some/ forward slas/hes'; const invertSlashes = str => {    let res = '';    for(let i = 0; i < str.length; i++){       if(str[i] !== '/'){          res += str[i];          continue; ... Read More

We are required to write a JavaScript function that takes in a string and checks whether it is sorted or not.For example −isSorted('adefgjmxz')  // true isSorted('zxmfdba')     // true isSorted('dsfdsfva')     // falseExampleFollowing is the code −const str = 'abdfhlmxz'; const findDiff = (a, b) => a.charCodeAt(0) - b.charCodeAt(0); const isStringSorted = (str = '') => {    if(str.length < 2){       return true;    };    let res = ''    for(let i = 0; i < str.length-1; i++){       if(findDiff(str[i+1], str[i]) > 0){          res += 'u';     ... Read More

Suppose, we have an array of objects like this −const array = [    {key: 'a', value: false},    {key: 'a', value: 100},    {key: 'a', value: null},    {key: 'a', value: 23} ];We are required to write a JavaScript function that takes in one such array and places all the objects that have falsy values for the "value" property to the bottom and sorts all other objects in decreasing order by the "value" property.ExampleFollowing is the code −const arr = [    {key: 'a', value: false},    {key: 'a', value: 100},    {key: 'a', value: null},    {key: 'a', ... Read More

We are required to write a JavaScript function that takes in a string which contains English alphabet, for example −const str = 'This is a sample string, will be used to collect some data';The function should return an object containing the count of vowels and consonants in the string i.e. the output should be −{ vowels: 17, consonants: 29 }ExampleFollowing is the code −const str = 'This is a sample string, will be used to collect some data'; const countAlpha = str => {    return str.split('').reduce((acc, val) => {       const legend = 'aeiou';       ... Read More