Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Economics & Finance
In this tutorial, we are going to create a Rectangle with background colour using FabricJS. Rectangle is one of the various shapes provided by FabricJS. In order to create a rectangle, we will have to create an instance of fabric.Rect class and add it to the canvas. The backgroundColor property allows us to assign a colour to our object's background. It is the colour of the container where the rectangle lives and is rectangular in shape for the rectangle. Syntax new fabric.Rect({ backgroundColor: String }: Object) Parameters ... Read More
In this tutorial, we are going to learn how to include Text object's default values in its serialization using FabricJS. We can display text on canvas by adding an instance of fabric.Text. Not only does it allow us to move, scale and change the dimensions of the text but we can also add additional functionalities. Serialization is used in order to export canvas contents. In order to achieve this we use toObject() and toJSON() methods. The includeDefaultValues property allows us to include or omit the object's default values when being serialized. Syntax new fabric.Text(text: String, { includeDefaultValues: ... Read More
In this tutorial, we will show how you can use Parsley.js, which is a JavaScript library that is mainly used to validate forms. Parsley helps in validating the forms in a very subtle and easy manner, and it is one of the widely used form validation libraries out there. Features of Parsley.js There are plenty of reasons why Parsley is a good choice for validating your JavaScript forms. Some of them are mentioned below. Intuitive DOM API − The DOM API allows you ... Read More
In JavaScript, swapping adjacent words in a string means exchanging pairs of words - the first word with the second, the third with the fourth, and so on. If there's an odd number of words, the last word remains in its position. Example Here's how to swap adjacent words using the reduce method: const str = "This is a sample string only"; const replaceWords = str => { return str.split(" ").reduce((acc, val, ind, arr) => { if(ind % 2 === 1){ ... Read More
In JavaScript, arrays can contain undefined values which require special handling during sorting. By default, the sort() method converts all elements to strings, placing undefined values at the end of the sorted array. Let's explore different approaches to sort arrays containing undefined values effectively. Default Behavior with sort() When using the basic sort() method on arrays with undefined, JavaScript automatically places undefined values at the end: var namearr = ["Zebra", "Yatch", undefined, "Egg", undefined]; namearr.sort(); ... Read More
When working with arrays of objects, you often need to count occurrences based on unique key values. This is particularly useful for data analysis, grouping records, or creating summary statistics. The Problem Given an array of objects with nested properties, we want to count how many times each unique user appears: const arr = [ { assigned_user: { name: 'Paul', ... Read More
In a grid navigation problem, we need to find the number of unique paths from the top-left corner (0, 0) to the bottom-right corner (m-1, n-1) of an m×n grid, where movement is restricted to only right or down directions. This is a classic dynamic programming problem. Each cell's value represents the number of ways to reach that position from the starting point. Algorithm Explanation The solution uses dynamic programming with these key principles: First row and first column have only 1 path each (straight line) For any other cell, paths = paths from above ... Read More
We need to write a JavaScript function that takes an integer num and returns an array where each element represents the count of 1s in the binary representation of numbers from 0 to num. Problem Given a number num, create an array where: Index i contains the count of 1s in binary representation of i Array includes elements for numbers 0 through num (inclusive) For example, if num = 4: Input: 4 Output: [0, 1, 1, 2, 1] Output Explanation Let's break down the binary representations: Number ... Read More
We are required to write a JavaScript function that takes in two numbers, let say m and n. Our function should construct and return an array of first n natural multiples of m. Problem Statement Given two numbers m and n, we need to create a function that returns an array containing the first n multiples of m. For example, if m = 6 and n = 5, the function should return [6, 12, 18, 24, 30]. Method 1: Using a For Loop The most straightforward approach is to use a for loop to iterate ... Read More
The crypto.scrypt() method provides an asynchronous implementation of the scrypt password-based key derivation function. Scrypt is designed to be computationally expensive and memory-intensive, making it resistant to brute-force attacks by requiring significant resources to compute. Syntax crypto.scrypt(password, salt, keylen, [options], callback) Parameters The parameters are described below: password – The password to derive a key from. Can be a string, Buffer, TypedArray, or DataView. ... Read More