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We are required to write a JavaScript function that takes in a string. It should print out each number for every corresponding letter in the string. For example, a = 1 b = 2 c = 3 d = 4 e = 5 . . . Y = 25 Z = 26 Therefore, if the input is "hello man", Then the output should be a number for each character − "8, 5, 12, 12, 15, 13, 1, 14" How It Works The solution uses the charCodeAt() method to get ... Read More
The shiftKey property is a boolean property of mouse events that indicates whether the Shift key was pressed when the mouse event occurred. This property is commonly used to modify the behavior of mouse interactions based on keyboard modifiers. Syntax event.shiftKey Return Value The shiftKey property returns: true - if the Shift key was pressed during the mouse event false - if the Shift key was not pressed during the mouse event Example: Basic shiftKey Detection Here's how to detect if the Shift key ... Read More
localStorage is used to persist information across multiple sessions. It has a maximum size of 5MB in most browsers and stores data as key-value pairs. Understanding localStorage Size Calculation Each character in localStorage is stored as UTF-16, taking 2 bytes. To calculate the size, we multiply the string length by 2 and convert to MB. Example: Calculate localStorage Size You can try to run the following code snippet to check the size allocated: localStorage Size Calculator localStorage Size Breakdown ... Read More
Graph traversal (also known as graph search) refers to the process of visiting (checking and/or updating) each vertex in a graph. Such traversals are classified by the order in which the vertices are visited. In JavaScript, the two most common graph traversal algorithms are Breadth-First Search (BFS) and Depth-First Search (DFS). Both algorithms systematically explore graph nodes but use different strategies. Graph Representation First, let's create a simple graph using an adjacency list representation: class Graph { constructor() { this.adjacencyList = {}; ... Read More
Dynamic programming breaks down complex problems into smaller sub-problems and stores their solutions to avoid redundant calculations. This technique is particularly useful for optimization problems where overlapping sub-problems exist. Dynamic programming is used where we have problems that can be divided into similar sub-problems so that their results can be re-used. Before solving a sub-problem, the algorithm checks if it has already been solved and stored. The solutions of sub-problems are combined to achieve the optimal solution. When to Use Dynamic Programming For a problem to benefit from dynamic programming: The ... Read More
To update a specific index in a boolean matrix in JavaScript, you can directly access the element using array indexing and assign a new boolean value. Let's explore different approaches to create and modify boolean matrices. Creating a Boolean Matrix First, let's create a boolean matrix using the fill() method: const array = Array(4); var fillWithTrueValue = array.fill(true); const matrixWithOnlyBooleanTrue = Array(4).fill(fillWithTrueValue); console.log("Original matrix:"); console.log(matrixWithOnlyBooleanTrue); Original matrix: [ [ true, true, true, true ], [ true, true, true, true ], [ true, true, true, true ], ... Read More
To get the time difference between two timestamps in seconds, you can subtract one Date object from another and divide by 1000. JavaScript Date objects return milliseconds when subtracted, so dividing by 1000 converts to seconds. Basic Time Difference in Seconds The simplest approach is to subtract two Date objects and convert milliseconds to seconds: Time Difference in Seconds var date1 = new Date("Jan 1, 2018 11:10:05"); ... Read More
In this tutorial, we will learn how to play a multimedia file using JavaScript. The multimedia file is the audio and video files. The multimedia files can be of different formats. wav and mp3 are two examples of audio file formats, whereas mp4 and mkv are examples of video file formats. In HTML, multimedia files can be shown easily using different tags. We use the video tag for showing a video, and for audio, we use the audio tag. These two tags are quite similar, and many attributes are the same in both tags. The "src" attribute defines ... Read More
In JavaScript, an empty array [] converts to an empty string "" when converted to a string. This happens through JavaScript's automatic type conversion or by using explicit conversion methods. Using String() Method The String() method explicitly converts any value to a string: Convert [] to String var myVal = []; document.write("String: " + String(myVal)); document.write("Type: " + typeof String(myVal)); ... Read More
Drawing an oval in HTML5 canvas can be achieved by scaling a circle. Since canvas doesn't have a built-in oval method, we use the scale() transformation to stretch a circle into an elliptical shape. How It Works The technique involves three steps: Save the current canvas state with save() Apply scaling transformation to stretch the circle Draw a circle using arc(), which appears as an oval due to scaling Restore the original state with restore() Example HTML5 Canvas Oval ... Read More