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Articles on Trending Technologies
Technical articles with clear explanations and examples
Call a function with onclick() – JavaScript?
The onclick event is a fundamental feature for calling functions in JavaScript when users interact with HTML elements. This event allows you to execute JavaScript code in response to mouse clicks on buttons, links, or any clickable element. What is the Onclick Event? The onclick event is triggered when a user clicks on an HTML element. It's commonly used to execute JavaScript functions in response to user interactions, making web pages interactive and responsive. You can call a function using the onclick event in two main ways: Using the onclick Attribute ...
Read MoreConstructing an object from repetitive numeral string in JavaScript
Suppose, we have a string with digits like this − const str = '11222233344444445666'; We are required to write a JavaScript function that takes in this string and returns an object that represents the count of each number in the string. So, for this string, the output should be − const output = { "1": 2, "2": 4, "3": 3, "4": 7, "5": 1, "6": 3 }; Using a for Loop The most straightforward approach is to iterate ...
Read MoreFind the minimum and maximum values that can be calculated by summing exactly four of the five integers in JavaScript
Given an array of five positive integers, we are required to find the minimum and maximum values that can be calculated by summing exactly four of the five integers. Then print the respective minimum and maximum values as a single line of two space-separated long integers. The array is not sorted all the times. For example: const arr = [1, 3, 5, 7, 9] The minimum sum is: 1 + 3 + 5 + 7 = 16 and the maximum sum is: 3 + 5 + 7 ...
Read MoreBuild tree array from JSON in JavaScript
Building a tree structure from a flat array is a common task in JavaScript. When you have hierarchical data represented as a flat array with codes indicating parent-child relationships, you can transform it into a nested tree structure. The Problem Suppose we have the following flat array where the code property indicates hierarchy through dot notation: const arr = [{ "code": "2", "name": "PENDING" }, { "code": "2.2", "name": "PENDING CHILDREN" }, { "code": "2.2.01.01", ...
Read MoreFlattening a JSON object in JavaScript
Flattening a JSON object means converting a nested object structure into a single-level object where nested keys are represented using dot notation. This technique is useful for data processing, form handling, and API transformations. Suppose we have the following JSON object that may contain nesting up to any level: const obj = { "one": 1, "two": { "three": 3 }, "four": { "five": 5, "six": { "seven": 7 ...
Read MoreNumber of carries required while adding two numbers in JavaScript
When adding two numbers on paper, we sometimes need to "carry" a digit to the next column when the sum of digits exceeds 9. This article shows how to count the total number of carries required during addition. Problem We need to write a JavaScript function that takes two numbers and counts how many carries are needed when adding them digit by digit, just like manual addition on paper. For example, when adding 179 and 284: 9 + 4 = 13 (carry 1) 7 + 8 + 1 = 16 (carry 1) 1 + 2 + ...
Read MoreHow to create a canvas with Image using FabricJS?
In this tutorial, we are going to learn how to create a canvas with Image using FabricJS. We can create an Image object by creating an instance of fabric.Image. Since it is one of the basic elements of FabricJS, we can also easily customize it by applying properties like angle, opacity etc. Syntax new fabric.Image(element, options, callback) Parameters element − This parameter accepts HTMLImageElement, HTMLCanvasElement, HTMLVideoElement or String which denotes the image element. The String should be a URL and would be loaded as an image. ...
Read MoreHow to replace before first forward slash - JavaScript?
Let's say the following is our string with forward slash — var queryStringValue = "welcome/name/john/age/32" To replace before first forward slash, use replace() along with regular expressions. Syntax string.replace(/^[^/]+/, "replacement") Example Following is the code — var regularExpression = /^[^/]+/ var queryStringValue = "welcome/name/john/age/32" var replacedValue = queryStringValue.replace(regularExpression, 'index'); console.log("Original value=" + queryStringValue); console.log("After replacing the value=" + replacedValue); Original value=welcome/name/john/age/32 After replacing the value=index/name/john/age/32 How the Regular Expression Works The regular expression /^[^/]+/ breaks down as follows: ^ ...
Read MoreFinding the first unique element in a sorted array in JavaScript
Suppose we have a sorted array of literals like this: const arr = [2, 2, 3, 3, 3, 5, 5, 6, 7, 8, 9]; We are required to write a JavaScript function that takes in one such array and returns the first number that appears only once in the array. If there is no such number in the array, we should return false. For this array, the output should be 6. Using Index Comparison Method Since the array is sorted, we can check if an element is unique by comparing it with ...
Read MoreGroup all the objects together having the same value for the '_id' key in JavaScript
Suppose we have an array of objects like this − const arr = [ {_id : "1", S : "2"}, {_id : "1", M : "4"}, {_id : "2", M : "1"}, {_id : "" , M : "1"}, {_id : "3", S : "3"} ]; We are required to write a JavaScript function that takes in one such array and groups all the objects together that have the same value for the '_id' key. Therefore, the final output should ...
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