Let’s say, we have an array of objects like this −const arr = [    {"name1": "firstString"},    {"name2": "secondString"},    {"name3": "thirdString"},    {"name4": "fourthString"},    {"name5": "fifthString"},    {"name6": "sixthString"}, ];We are required to write a function that takes one such array of objects and returns an object with all the properties listed in that object.So, let’s write the code for this function. It can be done through the Array reduce method −Exampleconst arr = [    {"name1": "firstString"},    {"name2": "secondString"},    {"name3": "thirdString"},    {"name4": "fourthString"},    {"name5": "fifthString"},    {"name6": "sixthString"}, ]; const reduceArray = ... Read More

Let’s say, we have to write a function remove Nth that takes in an array and a number n and it removes every nth element of the array in place.This can be done using the Array.prototype.splice() method and here is the code for doing so −Exampleconst arr = ['T', 'h', 'a', 'i', 's', 'b', ' ', 'i', 'c', 's', ' ', 'a', 't', 'h', 'e', 'e', ' ', 't', 's', 'o', 'r', 'n', 'g', 't', ' ', 't', 'n', 'h', 'a', 's', 't', ' ', 'o', 'n', 'e', 'o', 'v', 'e', 'a', 'r', ' ', 'f', 'e', 'n', 'a', 'd', ... Read More

We have to write a function that returns the lowest index at which a value (second argument) should be inserted into an array (first argument) once it has been sorted (either in ascending or descending order). The returned value should be a number.For example, Let’s say, we have a function getIndexToInsert() −getIndexToInsert([1, 2, 3, 4], 1.5, ‘asc’) should return 1 because it is greater than 1 (index 0), but less than 2 (index 1).Likewise, getIndexToInsert([20, 3, 5], 19, ‘asc’) should return 2 because once the array has been sorted in ascending order it will look like [3, 5, 20] and ... Read More

We are required to write a JavaScript function, say checkThree() that takes in an array and returns true if anywhere in the array there exists three consecutive elements that are identical (i.e., have the same value) otherwise it returns false.Therefore, let’s write the code for this function −Exampleconst arr = ["g", "z", "z", "v" ,"b", "b", "b"]; const checkThree = arr => {    const prev = {       element: null,       count: 0    };    for(let i = 0; i < arr.length; i++){       const { count, element } = prev;   ... Read More

Consider the following binary array (Array A) −const arr = [1, 0, 1, 1, 1, 1, 0, 1, 1];When this array is passed through the function, say sumRight(), it produces the following output array (Array B) −const output = [1, 0, 4, 3, 2, 1, 0, 2, 1];Understanding the functionElements in array arr can be either 0 or 1. The function counts backward from the last element of array arr, if there are consecutive 1's in the array arr then the corresponding element in the output array will be 1 but for the 2nd consecutive 1 in array arr, it ... Read More

Let’s say. we have an array and an object like this −const arr = ['a', 'd', 'f']; const obj = {    "a": 5,    "b": 8,    "c": 4,    "d": 1,    "e": 9,    "f": 2,    "g": 7 };We are required to write a function that takes in the object and the array and filter away all the object properties that are not an element of the array. So, the output should only contain 3 properties, namely: “a”, “d” and “e”.Let’s write the code for this function −Exampleconst arr = ['a', 'd', 'f']; const obj = ... Read More

We are required to write a sorting function that sort an array based on the contents of another array.For example − We have to sort the original array such that the elements present in the below sortOrder array appear right at the start of original array and all other should keep their order −const originalArray = ['Apple', 'Cat', 'Fan', 'Goat', 'Van', 'Zebra']; const sortOrder = ['Zebra', 'Van'];Exampleconst originalArray = ['Apple', 'Cat', 'Fan', 'Goat', 'Van', 'Zebra']; const sortOrder = ['Zebra', 'Van']; const sorter = (a, b) => {    if(sortOrder.includes(a)){       return -1;    };    if(sortOrder.includes(b)){     ... Read More

We are required to write a function that returns the index of the very first element that appears at least twice in the array. If no element appears more than once, we have to return -1. The condition is that we have to do this in constant space (i.e., without utilizing extra memory).Let’s devise the solution for this problem. We will use a for loop to iterate over the array and use the Array.prototype.lastIndexOf() method to check for duplicates.Exampleconst firstDuplicate = arr => {    for(let i = 0; i < arr.length; i++){       if(arr.lastIndexOf(arr[i]) !== i){   ... Read More

We are required to write a function that takes in a one-dimensional array as the first argument and a number n as the second argument and we have to make n subarrays inside of the parent array (**if possible) and divide elements into them accordingly.** if the array contains 9 elements and we asked to make 4 subarrays, then dividing 2 elements in each subarray creates 5 subarrays and 3 in each creates 3, so in such cases we have to fallback to nearest lowest level (3 in this case) because our requirement is to distribute equal number of elements ... Read More

There are times when you need to merge multiple Boolean arrays into a single array in JavaScript. One common approach is to combine the corresponding elements from each array using the OR (||) operator. This operation returns true if at least one of the elements being compared is true; otherwise, it returns false. In this article, we'll learn how to merge multiple Boolean arrays into a single array using JavaScript, specifically by applying the OR operator on corresponding elements. We will utilize the Array.prototype.reduce() function to efficiently perform this task. Problem Definition We are given an array of arrays of ... Read More