Problem Description: Find the number of pairs in a given array arr that add up to produce a given number k. Basic Approach: function findPairs(arr, k) { let numOfPairs = 0; // 'numerOfPairs' will return double the actual number of pairs because of nested...
Array.map() Polyfill const array = [1,2,3,4,5]; Array.prototype.myMap = function(callback) { let result = []; for (let i = 0; i < this.length; i++) { result.push(callback(this[i], i, this)); } return result; } let answer1 = array.map((element) => element * 2);...
What is a synthetic event? How do we create a synthetic event?
In React, the Virtual DOM (Document Object Model) is a concept and technique used to efficiently update the user interface (UI) by minimizing direct manipulations to the actual browser DOM. When we use React to build an application, we define the UI using React...
Debouncing Debouncing is a programming technique used to limit the number of invocations of a time-consuming function in order to improve the application performance. const debounce = (func, delay) => { let timerId = null; if (timerId) { clearTimeout(timerId); }...
In JavaScript, lexical environment is a data structure that holds variable and function declarations during the execution of the program. It consists of two main components: an environment record and a reference to the outer environment (aka outer/parent scope). The...
A closure in JavaScript refers to the capability of a function to retain access to variables and other resources from the scope in which it was defined, even when the function is executed outside that scope. It allow a function to remember and access its surrounding...
Promises and async/await features introduced in ES6 and ES8 respectively, are used for handling asynchronous operations, but they have different syntax and approaches.
