We are required to depict the ways in which we can access the current timestamp in JavaScript in −---seconds---millisecondsJavaScript works with the number of milliseconds since the epoch whereas most other languages work with the seconds.This will give you a Unix timestamp (in seconds) −const date = new Date(); const unix = Math.round(+date / 1000); console.log(unix);This will give you the milliseconds since the epoch (not Unix timestamp) −const date = new Date(); const milliseconds = date.getTime(); console.log(milliseconds);

We are required to write a JavaScript function that takes in an array of Numbers as the first argument and a number, say n, as the second argument.Our function should calculate and return the greatest possible product of n numbers from the array.ExampleThe code for this will be −const getHighestProduct = (arr, num) => {    let prod = 1;    const sorter = (a, b) => a - b;    arr.sort(sorter);    if (num > arr.length || num & 2 && arr[arr.length - 1] < 0) {       return;    };    if (num % 2) { ... Read More

Suppose, we have an array of nested objects like this −const arr = [{    id: 1,    legs:[{       carrierName:'Pegasus'    }] }, {    id: 2,    legs:[{       carrierName: 'SunExpress'    },    {       carrierName: 'SunExpress'    }] }, {    id: 3,    legs:[{       carrierName: 'Pegasus'    },    {       carrierName: 'SunExpress'    }] }];We are required to write a JavaScript function that takes one such array as the first argument and a search query string as the second argument.Our function should filter ... Read More

Suppose, we have the following array in JavaScript −const arr = [{    "code": "2",    "name": "PENDING" }, {    "code": "2.2",    "name": "PENDING CHILDREN" }, {    "code": "2.2.01.01",    "name": "PENDING CHILDREN CHILDREN" }, {    "code": "2.2.01.02",    "name": "PENDING CHILDREN CHILDREN02" }, {    "code": "1",    "name": "ACTIVE" }, {    "code": "1.1",    "name": "ACTIVE CHILDREN" }, {    "code": "1.1.01",    "name": "ACTIVE CHILDREN CHILDREN" }];We are required to write a JavaScript function that takes in one such array. The function should build a tree structure from this array based on ... Read More

Suppose, we have an array of objects that contains data about some fruits and vegetables like this −const arr = [    {food: 'apple', type: 'fruit'},    {food: 'potato', type: 'vegetable'},    {food: 'banana', type: 'fruit'}, ];We are required to write a JavaScript function that takes in one such array.Our function should then group the array objects based on the "type" property of the objects.It means that all the "fruit" type objects are grouped together and the "vegetable' type grouped together separately.ExampleThe code for this will be −const arr = [    {food: 'apple', type: 'fruit'},    {food: 'potato', type: ... Read More

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