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Articles on Trending Technologies
Technical articles with clear explanations and examples
Sum all duplicate value in array - JavaScript
We are required to write a JavaScript function that takes in an array of numbers with duplicate entries and sums all the duplicate entries to one index. For example − If the input array is − const input = [1, 3, 1, 3, 5, 7, 5, 4]; Then the output should be − const output = [2, 6, 7, 10, 4]; Using Map to Track and Sum Duplicates The most efficient approach is to use a Map to count occurrences and then multiply each unique value by its count: ...
Read MoreAdding two values at a time from an array - JavaScript
Let's say, we are required to write a JavaScript function that takes in an array of Numbers and returns a new array with elements as sum of two consecutive elements from the original array. For example, if the input array is − const arr = [3, 6, 3, 87, 3, 23, 2, 2, 6, 8]; Then the output should be − const output = [9, 90, 26, 4, 14]; Example Following is the code − const arr = [3, 6, 3, 87, 3, 23, 2, 2, 6, 8]; ...
Read MoreHow to search the alternate text of an image-map area in JavaScript?
To search the alternate (alt) text of an image-map area in JavaScript, use the alt property. This property allows you to access or modify the alternative text that describes the image map area for accessibility purposes. Syntax // Get alt text let altText = areaElement.alt; // Set alt text areaElement.alt = "new alt text"; Example: Accessing Alt Text of Image Map Area ...
Read MoreDoes HTML5 allow you to interact with local client files from within a browser?
HTML5 allows web applications to interact with local client files through powerful APIs. These interfaces enable browsers to access the user's file system, read binary data, and handle file operations that were previously impossible with standard web technologies. HTML5 File APIs HTML5 provides three main APIs for file interaction: File API - Read file contents and metadata File System API - Access file system structure (deprecated in modern browsers) File Writer API - Write data to files (limited browser support) Reading Local Files The ...
Read MoreHow to check if a document is ready in JavaScript?
In JavaScript, you can check if the DOM is fully loaded using document.readyState or event listeners. This is crucial for ensuring your scripts run after the HTML structure is ready. Understanding document.readyState The document.readyState property has three possible values: "loading" - The document is still loading "interactive" - The document has loaded but resources like images may still be loading "complete" - The document and all resources have finished loading Method 1: Using document.readyState Document Ready ...
Read MoreHow to find a group of three elements in an array whose sum equals some target sum JavaScript
We need to write a function that finds three elements in an array whose sum equals a target value. The function should return the indices of these three elements, or -1 if no such triplet exists. Approach We'll use a two-step approach: Create a twoSum() helper function that finds two numbers adding up to a target sum Iterate through each element and use twoSum() to find the remaining two elements This approach has O(N²) time complexity, where N is the array length. How It Works The twoSum() function uses a hash map ...
Read MoreFind unique and biggest string values from an array in JavaScript
In JavaScript, we often need to filter arrays to get unique values and sort them by specific criteria. This article demonstrates how to find the longest unique string values from an array of objects. Problem Statement Given an array of objects with text properties, we need to create a function that returns n objects with the longest unique string values. If fewer than n unique objects exist, return all unique objects. const arr = [ {text: 'use'}, {text: 'secur'}, {text: 'form'}, ...
Read MoreCreate new array without impacting values from old array in JavaScript?
In JavaScript, directly assigning an array to a new variable creates a reference to the original array, not a copy. This means changes to the new variable will affect the original array. To create a truly independent copy, you need to use specific cloning methods. The Problem with Direct Assignment When you assign an array directly, both variables point to the same array in memory: var originalArray = ["John", "Mike", "Sam", "Carol"]; var newArray = originalArray; // This creates a reference, not a copy newArray.push("David"); console.log("Original array:", originalArray); console.log("New array:", newArray); ...
Read MoreCounting the clusters of positive numbers - JavaScript Arrays
Let's say, we have an array of numbers like this − const arr = [-1, -2, -1, 0, -1, -2, -1, -2, -1, 0, 1, 0]; We are required to write a JavaScript function that counts the consecutive groups of non-negative (positives and 0) numbers in the array. Like here we have consecutive non-negatives from index 3 to 3 (only one element, but still a cluster) which forms one group and then from index 9 to end of array forms the second group. Therefore, for this array, the function should return 2. How It Works ...
Read MoreHow Is Infinity converted to Boolean in JavaScript?
In JavaScript, Infinity and -Infinity are special numeric values representing positive and negative infinity. When converting these values to Boolean, they always evaluate to true because they are considered "truthy" values. This tutorial demonstrates three methods to convert Infinity values to Boolean in JavaScript: Using the Boolean() Method Using the Logical NOT(!) Operator Converting Infinity to String to Boolean Using the Boolean() Method The Boolean() constructor converts any value to its boolean equivalent. For Infinity and -Infinity, this method returns true since both are truthy ...
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