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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to merge two object arrays of different size by key in JavaScript
When working with object arrays of different sizes, we often need to merge them based on a common key. This is useful when combining data from different sources that share a common identifier. Suppose we have an object like this: const obj = { "part1": [{"id": 1, "a": 50}, {"id": 2, "a": 55}, {"id": 4, "a": 100}], "part2":[{"id": 1, "b": 40}, {"id": 3, "b": 45}, {"id": 4, "b": 110}] }; We need to merge part1 and part2 arrays to form a single array where objects with the same id ...
Read MoreFinding square root of a number without using Math.sqrt() in JavaScript
We are required to write a JavaScript function that takes in a positive integer as the only argument. The function should find and return the square root of the number provided as the input. Newton's Method (Recommended) The most efficient approach is Newton's method (also called the Babylonian method), which uses iterative approximation to converge on the square root. const squareRoot = (num, precision = 0) => { if (num deviation) { res -= ((res ** 2) - num) / (2 * res); ...
Read MoreMoving all zeroes present in the array to the end in JavaScript
We are required to write a JavaScript function that takes in an array of literals that might contain some 0s. Our function should tweak the array such that all the zeroes are pushed to the end and all non-zero elements hold their relative positions. Problem Given an array containing zeros and non-zero elements, we need to move all zeros to the end while maintaining the relative order of non-zero elements. Method 1: Using Two-Pass Approach This approach first collects non-zero elements, then adds zeros at the end: const arr = [5, 0, 1, 0, ...
Read MoreGreatest number divisible by n within a bound in JavaScript
Problem We need to write a JavaScript function that takes in a divisor number n and a bound number b. Our function should find the largest integer num, such that: num is divisible by n (the divisor) num is less than or equal to b (the bound) num is greater than 0 Brute Force Approach The straightforward approach is to iterate through all multiples of n and find the largest one within the bound: const n = 14; const b = 400; const biggestDivisible = ...
Read Moreprocess.chdir() Method in Node.js
The process.chdir() method changes the current working directory of the Node.js process. It throws an exception if the operation fails (such as when the specified directory doesn't exist) but returns no value on success. Syntax process.chdir(directory) Parameters directory – A string containing the path to the directory you want to change to. Return Value This method returns undefined on success and throws an error if the directory change fails. Example 1: Successful Directory Change // Node.js program to demonstrate process.chdir() const process = ...
Read MoreHow to create a Rectangle with wait cursor on hover over objects using FabricJS?
In this tutorial, we are going to create a Rectangle with a wait cursor on hover over objects using FabricJS. wait is one of the native cursor styles available which can be used in the FabricJS canvas too. FabricJS provides various types of cursors like default, all-scroll, crosshair, col-resize, row-resize, etc., that reuse the native cursor under the hood. The hoverCursor property sets the style of the cursor when hovered over a canvas object. Syntax new fabric.Rect({ hoverCursor: String }: Object) Parameters Options ...
Read MoreHow to set the background colour of text lines with Text using FabricJS?
In this tutorial, we are going to learn how to set the background colour of text lines with Text 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 it also provides additional functionality like text alignment, text decoration, line height which can be obtained by the properties textAlign, underline and lineHeight respectively. Similarly we can also set the background colour of text lines by using the textBackgroundColor property. Syntax new fabric.Text(text: String , { textBackgroundColor ...
Read MoreApply an IF condition to every element in an HTML table with JavaScript?
HTML tables are created using the tag with for table rows and for data cells. JavaScript allows you to apply conditional logic to each table element dynamically. This article demonstrates how to use JavaScript to apply if conditions to every element in an HTML table, enabling dynamic content modification based on specific criteria. Using document.querySelectorAll() with forEach() The document.querySelectorAll() method returns a static NodeList of all elements matching the specified CSS selector. Combined with forEach(), it allows you to iterate through table elements and apply conditions. Syntax document.querySelectorAll(selector).forEach(function(element) { ...
Read MoreMake strings in array become keys in object in a new array in JavaScript?
The task we are going to perform in this article is to make strings in an array become keys in objects within a new array in JavaScript. Let's consider a simple array: let array = ['bike', 'car']; We want to transform this array into a new array where each string becomes a key in an object with an empty array as its value: let newArray = [{bike: []}, {car: []}]; Let's explore different methods to accomplish this transformation in JavaScript. Using map() Method The map() method creates a new array ...
Read MoreReduce array in JavaScript
In JavaScript, arrays can be transformed using various methods. This article demonstrates how to extract and convert time values from an array of objects into a more usable format. Suppose we have an array of objects containing time strings: const arr = [ {"time":"18:00:00"}, {"time":"10:00:00"}, {"time":"16:30:00"} ]; We need to create a function that: Extracts the time strings from each object Converts times like "18:00:00" to arrays like [18, 0] Returns an array containing all converted time arrays Using map() to Transform ...
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