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Object Oriented Programming Articles
Page 186 of 589
Filter one array with another array - JavaScript
In JavaScript, filtering one array based on another array is a common task. This technique is useful when you need to keep only certain elements from an array based on criteria stored in another array. Problem Setup Consider the following arrays: const main = [ {name: "Karan", age: 34}, {name: "Aayush", age: 24}, {name: "Ameesh", age: 23}, {name: "Joy", age: 33}, {name: "Siddarth", age: 43}, {name: "Nakul", age: 31}, ...
Read MoreThe Zombie Apocalypse case study - JavaScript
A nasty zombie virus is spreading out in the digital cities. We work at the digital CDC and our job is to look over the city maps and tell which areas are contaminated by the zombie virus so the digital army would know where to drop the bombs. They are the new kind of digital zombies which can travel only in vertical and horizontal directions and infect only numbers same as them. We'll be given a two-dimensional array with numbers in it. For some mysterious reason patient zero is always found in north west area of the ...
Read MoreFinding the length of a JavaScript object
JavaScript objects don't have a built-in length property like arrays. However, there are several methods to find the number of properties in an object. Suppose we have an object like this: const obj = { name: "Ramesh", age: 34, occupation: "HR Manager", address: "Tilak Nagar, New Delhi", experience: 13 }; We need to count the number of properties in this object. Using Object.keys() (Recommended) The most common and reliable method is Object.keys(), which returns an array of the object's property names: ...
Read MoreSorting an array of objects by property values - JavaScript
In JavaScript, you can sort an array of objects by property values using the Array.sort() method with a custom comparison function. This is particularly useful when working with data structures like product catalogs, user lists, or any collection of objects. Sample Data Let's work with this array of home objects: const homes = [ { "h_id": "3", "city": "Dallas", "state": "TX", ...
Read MoreCapitalize letter in a string in order and create an array to store - JavaScript
We are required to write a JavaScript function that takes in a string and turns it into a Mexican Wave i.e. resembling string produced by successive capital letters in every word. For example, if the string is: const str = 'edabit'; Then the output should be the following with successive single capital letters: const output = ["Edabit", "eDabit", "edAbit", "edaBit", "edabIt", "edabiT"]; Method 1: Using String Prototype Extension This approach extends the String prototype with a custom replaceAt method: const str = 'edabit'; const replaceAt = function(index, ...
Read MoreRecursion problem Snail Trail in JavaScript
The snail trail problem involves traversing a 2D array in a spiral pattern from outside to inside. Given a square matrix, we need to create a flat array by following the spiral path: right → down → left → up, repeating until we reach the center. Suppose, we have an array like this: const arr = [ [1, 2, 3, 4], [12, 13, 14, 5], [11, 16, 15, 6], [10, 9, 8, 7] ]; The array is bound to be a square matrix. We are required to ...
Read MoreFind closest index of array in JavaScript
When working with arrays in JavaScript, you might need to find the index of the element that is numerically closest to a given target value. This is useful in scenarios like finding the nearest data point, closest price match, or similar proximity-based searches. Problem Statement Given an array of numbers and a target value, we need to find the index of the array element that has the smallest absolute difference from the target. const arr = [2, 42, 82, 122, 162, 202, 242, 282, 322, 362]; For example, if our target is 150, we ...
Read MoreJavaScript Sleep() function?
JavaScript doesn't have a built-in sleep() function like other languages (C's sleep(), Java's Thread.sleep(), Python's time.sleep()). However, we can create one using Promises and async/await. Creating a Sleep Function We can implement a sleep function using setTimeout() wrapped in a Promise: function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); } Using Sleep with Promises function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); } console.log("Start"); sleep(2000).then(() => { console.log("After 2 seconds"); }); Start ...
Read MoreHow to Create GUID / UUID in JavaScript?
A Globally Unique Identifier (GUID) or Universally Unique Identifier (UUID) is a 128-bit value used as a unique identifier in software development. It's typically represented as a 32-character hexadecimal string with hyphens, like: de305d84-75c4-431d-acc2-eb6b0e5f6014. Here are several JavaScript methods to generate GUIDs/UUIDs. Using Random Number Generation The most common approach uses Math.random() to generate a UUID v4 format: function generate_uuidv4() { return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) { var uuid = Math.random() * 16 | 0, v = c == 'x' ? uuid : (uuid & 0x3 ...
Read MoreHow to use finally on promise with then and catch in Javascript?
JavaScript asynchronous programming uses promise objects that don't block execution but signal when operations complete. Promises can either resolve successfully or reject with an error. The finally() method executes cleanup code regardless of the promise outcome, similar to finally blocks in synchronous try-catch statements. Syntax promise .then(result => { // handle success }) .catch(error => { // handle error }) .finally(() => { // ...
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