We are required to write a JavaScript function that takes in an array of strings. Our function should iterate through the array and find and return the longest string from the array.Our function should do this without changing the content of the input array.ExampleThe code for this will be −const arr = ["aaaa", "aa", "aa", "aaaaa", "acc", "aaaaaaaa"]; const findLargest = (arr = []) => {    if(!arr?.length){       return '';    };    let res = '';    res = arr.reduce((acc, val) => {       return acc.length >= val.length ? acc : val;    });    return res; }; console.log(findLargest(arr));OutputAnd the output in the console will be −aaaaaaaa

We are required to write a JavaScript function that takes in an array of Numbers.The array might contain some repeating / duplicate entries within it. Our function should add all the duplicate entries and return the new array thus formed.ExampleThe code for this will be −const arr = [20, 20, 20, 10, 10, 5, 1]; const sumIdentical = (arr = []) => {    let map = {};    for (let i = 0; i < arr.length; i++) {       let el = arr[i];       map[el] = map[el] ? map[el] + 1 : 1;    };    const res = [];    for (let count in map) {       res.push(map[count] * count);    };    return res; }; console.log(sumIdentical(arr));OutputAnd the output in the console will be −[ 1, 5, 20, 60 ]

Suppose, we have an array of objects like this −const arr = [    { region: "Africa", fruit: "Orange", user: "Gary" },    { region: "Africa", fruit: "Apple", user: "Steve" },    { region: "Europe", fruit: "Orange", user: "John" },    { region: "Europe", fruit: "Apple", user: "bob" },    { region: "Asia", fruit: "Orange", user: "Ian" },    { region: "Asia", fruit: "Apple", user: "Angelo" },    { region: "Africa", fruit: "Orange", user: "Gary" } ];We are required to write a JavaScript function that takes in one such array. The function should prepare a new array of objects that ... Read More

Suppose, we have a JSON array with key/value pair objects like this −const arr = [{    "key": "name",    "value": "john" }, {    "key": "number",    "value": "1234" }, {    "key": "price",    "value": [{       "item": [{          "item": [{             "key": "quantity",             "value": "20"          },          {             "key": "price",             "value": "200"          }]       }] ... Read More

In this article, we will learn array sorting by level in JavaScript, creating a hierarchical tree structure from a flat array is a common challenge when dealing with relational data. This is a common task when dealing with hierarchical data, such as organizational charts, category trees, or file systems, where relationships like parent-child need to be represented. Problem Statement We have an array of objects representing nodes with _id, level, and parentId properties. Our goal is to transform this array into a tree structure where nodes are nested as children under their respective parents. The elements with the highest level ... Read More

We have a complex json file that we have to handle with JavaScript to make it hierarchical, in order to later build a tree.Every entry of the JSON array has −id − a unique id, parentId − the id of the parent node (which is 0 if the node is a root of the tree)level − the level of depth in the treeThe JSON data is already "ordered", means that an entry will have above itself a parent node or brother node, and under itself a child node or a brother node.The input array is −const arr = [   ... Read More

Suppose, we have the following array of arrays −const arr = [    [       ['dog', 'Harry'], ['age', 2]    ],    [       ['dog', 'Roger'], ['age', 5]    ] ];We are required to write a JavaScript function that takes in one such nested array. The function should then prepare an object based on the array.The object for the above array should look like −const output = [    {dog: 'Harry', age: 2},    {dog: 'Roger', age: 5} ];ExampleThe code for this will be −const arr = [    [       ['dog', 'Harry'], ['age', ... Read More

We are required to write a JavaScript function that takes in an array of literal values. The function should then count the frequency of each element of the input array and prepare a new array on that basis.For example − If the input array is −const arr = [5, 5, 5, 2, 2, 2, 2, 2, 9, 4];Then the output should be −const output = [    [5, 3],    [2, 5],    [9, 1],    [4, 1] ];ExampleThe code for this will be −const arr = [5, 5, 5, 2, 2, 2, 2, 2, 9, 4]; const frequencyArray = (arr = []) => {    const res = [];    arr.forEach(el => {       if (!this[el]) {          this[el] = [el, 0];          res.push(this[el])       };       this[el][1] ++    }, {});    return res; }; console.log(frequencyArray(arr));OutputAnd the output in the console will be −[ [ 5, 3 ], [ 2, 5 ], [ 9, 1 ], [ 4, 1 ] ]

Suppose, we have a reference to an object −let test = {};This object will potentially (but not immediately) have nested objects, something like −test = {level1: {level2: {level3: "level3"}}};We are required to write a JavaScript function that takes in one such object as the first argument and then any number of key strings as the arguments after.The function should determine whether or not the nested combination depicted by key strings exist in the object.ExampleThe code for this will be −const checkNested = function(obj = {}){    const args = Array.prototype.slice.call(arguments, 1);    for (let i = 0; i < args.length; ... Read More

In this article we are going to learn about “how to sort an array of integers correctly JavaScript”. Let’s look into the article to learn more about to sort an array. Sorting an array of integers is something that we’ve to do a lot in our JavaScript. The sort method lets us sort an array by passing in a comparator function. Sort() Method The sort() method enables you to order array elements sequentially. The sort() method modifies the positions of the elements in the initial array in addition to returning the sorted array. The array elements are ordinarily sorted by ... Read More