Suppose we have an object that contains information about the weather of a city −const obj = {    city: "New Delhi",    maxTemp: 32,    minTemp: 21,    humidity: 78,    aqi: 456,    day: 'Tuesday', };We are required to write a JavaScript function that takes in one such object. The function should construct an array of arrays based on this object where each subarray contains exactly two properties −the corresponding keythat key's valueTherefore, for the above object, the output should look like −const output = [    [ 'city', 'New Delhi' ],    [ 'maxTemp', 32 ],   ... Read More

We are required to write a JavaScript function that takes in two strings. Let’s call them str1 and str2.Our function should check either str1 starts with str2 or it ends with str2. If this is the case, we should return true otherwise we should return false.ExampleFollowing is the code −const str = 'this is an example string'; const startsOrEndsWith = (str1 = '', str2 = '') => {    if(str2.length > str1.length){       return false;    };    if(str1 === str2){       return true;    };    const { length: l1 } = str1;    const ... Read More

We are required to write a JavaScript function that takes in an array of Numbers as the only argument. The function should calculate and return the sum of alternative elements of the array.For example −If the input array is −const arr = [1, 2, 3, 4, 5, 6, 7];Then the output should be −1 + 3 + 5 + 7 = 16ExampleFollowing is the code −const arr = [1, 2, 3, 4, 5, 6, 7]; const alternativeSum = (arr = []) => {    let sum = 0;    for(let i = 0; i < arr.length; i++){       const el = arr[i];       if(i % 2 !== 0){          continue;       };       sum += el;    };    return sum; }; console.log(alternativeSum(arr));OutputFollowing is the output on console −16

The delete operator in JavaScript is actually an object operator (used with objects).But since arrays are also indexed objects in JavaScript, we can use the delete operator with arrays as well.Consider the following array of literals −const arr = ['a', 'b', 'c', 'd', 'e'];ExampleLet us now execute the following program and guess the expected output −const arr = ['a', 'b', 'c', 'd', 'e']; delete arr[4]; console.log(arr); console.log(arr.length);OutputThe output of this program in the console will be −[ 'a', 'b', 'c', 'd', ] 5Understanding the output −Since we deleted one index value of the array, we expected the array.length to ... Read More

We are required to write a JavaScript function that takes in a number as the first and the only argument. The function should use recursion to construct a string representing the binary notation of that number.For example −f(4) = '100' f(1000) = '1111101000' f(8) = '1000'ExampleFollowing is the code −const decimalToBinary = (num) => {    if(num >= 1) {       // If num is not divisible by 2 then recursively return proceeding       // binary of the num minus 1, 1 is added for the leftover 1 num       if (num % 2) ... Read More

We are required to write a JavaScript function that takes in a string as the only argument.The function should reverse the order of the words in the string and return the new string.The only condition is that we cannot use the inbuilt array method reverse().For example −If the input string is −const str = 'this is a string';Then the output string should be −const str = 'this is a string';ExampleFollowing is the code −const str = 'this is a string'; const reverseWordOrder = (str = '') => {    const strArr = str.split(' ');    let temp = '';   ... Read More

We are required to write a JavaScript function that takes in two arrays of numbers, let’s say arr1 and arr2. The function should find the intersection between the elements of the array. i.e., the elements that appear in both the arrays.The only condition is that if we encountered one element before as intersected, we should not consider it again even if appears again in both the arrays.For example −If the input arrays are −const arr1 = [1, 5, 7, 3, 1]; const arr2 = [1, 7, 3, 1, 6];Then the output array should be −const output = [1, 3, 7];However, ... Read More

We are required to write a JavaScript function that takes in an array of Numbers. The function should construct a new array based on the original array. Each corresponding element of the new array should be the product of all the elements of the original array including that element.For example −If the input array is −const arr = [1, 2, 3, 4, 5];Then the output array should be −const output = [120, 60, 40, 30, 24];We have to achieve this in linear time and constant space (obviously excluding the space used up in constructing the new array).ExampleFollowing is the code ... Read More

In this problem statement we have to find the largest difference between elements with a twist with the help of Javascript functionalities. So we will use basic Javascript to get the desired result. Understanding the problem The problem at hand is to find the largest difference between two items in an array. So we will add a twist to the problem. So we will not simply find the difference between two items but we will find the largest difference between an item and any smaller item that has appeared before in the array. And we will not rearrange ... Read More

In the given problem statement our task is to find the greatest product of three numbers with the help of Javascript functionalities. So we will use sorting technique first to get the last three highest items of the array and then calculate the product of those three elements to get the desired result. Understanding the Problem The problem at hand is to find the greatest product of three items or numbers present in the given array in Javascript. So we will have an array of integers and we will identify three numbers whose product is the largest among ... Read More