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The _.pluck() method was removed from lodash version 4 because it provided the same functionality as _.map(). This change was part of lodash's effort to reduce redundancy and improve consistency. What _.pluck() Did In lodash 3.x, _.pluck() extracted property values from a collection of objects: // Lodash 3.x syntax (no longer available) _.pluck(objects, 'propertyName') Replacement: Using _.map() In lodash 4+, use _.map() with a property path string to achieve the same result: const _ = require('lodash'); const objects = [{ 'a': 1 }, { 'a': 2 }, { 'a': 3 }]; ... Read More
The JavaScript let keyword, introduced in ES6 (2015), allows us to declare block-scoped variables. Unlike var, variables declared with let are only accessible within the block where they are defined. Block Scope with let Variables declared with let are confined to their block scope and cannot be accessed outside of it. JavaScript Let Example JavaScript Let Block Scope Test Block Scope ... Read More
JavaScript provides several methods to access child elements of a parent element. The most common approaches include using children, childNodes, querySelector, and querySelectorAll. Using the children Property The children property returns a live HTMLCollection of all direct child elements, excluding text nodes and comments. Getting Child Elements body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .child1, .child2, .child3 { display: none; ... Read More
We are required to write a function that flattens nested objects by converting deeply nested properties into dot-notation keys. This is useful for data transformation and API processing. If the input object is: const input = { a: 0, b: {x: {y: 1, z: 2}}, c: 3 }; Then the output of the function should be: const output = { a: 0, 'b.x.y': 1, 'b.x.z': 2, c: 3 } Recursive ... Read More
We are required to write a JavaScript function that takes in two strings and checks whether the first string starts with the second string or not. For example: If the two strings are: "Disaster management report" "Disas" Then our function should return true There are multiple ways to check if a string starts with another string in JavaScript. Let's explore the most common approaches. Using startsWith() Method (Recommended) The startsWith() method is the built-in and most straightforward way to check if a string starts with another string: const first = 'The ... Read More
In JavaScript, camel case formatting converts strings by lowercasing the first letter and capitalizing the first letter of each subsequent word, while removing all whitespace. What is Camel Case? Camel case is a naming convention where the first word starts with a lowercase letter and each subsequent word starts with an uppercase letter, with no spaces or punctuation. For example: "hello world" becomes "helloWorld". Using Regular Expression Method The most efficient approach uses a regular expression with the replace() method to transform the string: function convertStringToCamelCase(sentence) { return sentence.replace(/(?:^\w|[A-Z]|\b\w|\s+)/g, ... Read More
To add background music on a web page, you can use the element or the legacy tag. The modern approach uses HTML5's element with the autoplay attribute to start music automatically when the page loads. For background music, set the audio player to be hidden by using CSS or by omitting controls. The loop attribute makes the audio repeat continuously. Always upload your music file to the server and reference it in the src attribute. Method 1: Using HTML5 Audio Element (Recommended) The element is the modern standard for embedding audio content: ... Read More
In JavaScript, the columnCount property allows you to divide an element's content into multiple columns. This CSS property can be set and retrieved using JavaScript's style object. Syntax // Set column count element.style.columnCount = "number"; // Get column count let count = element.style.columnCount; Parameters The columnCount property accepts: number - The number of columns (e.g., "2", "3", "4") "auto" - Browser determines column count automatically "initial" - Sets to default value Example: Setting Column Count Click the button to divide the text into 4 columns: ... Read More
The HTML5 History API allows web applications to manipulate browser history programmatically, enabling single-page applications to update URLs without full page reloads. Understanding browser support is crucial for implementing this feature effectively. Browser Support Overview The HTML5 History API is now widely supported across modern browsers. WebKit-based browsers and Firefox 4 were among the first to implement this feature, but support has expanded significantly since then. Supported Browsers Firefox: Version 4 and above Google Chrome: All versions (since Chrome 5) Internet Explorer: Version ... Read More
HTML5 Application Cache and Browser Cache are two different caching mechanisms that serve distinct purposes in web development. Understanding their differences is crucial for optimizing web application performance. HTML5 Application Cache HTML5 Application Cache (AppCache) was a mechanism that allowed web applications to work offline by explicitly defining which resources should be cached. It used a manifest file to specify cacheable resources. // Example manifest file (cache.manifest) CACHE MANIFEST # Version 1.0 CACHE: index.html styles.css script.js logo.png NETWORK: * FALLBACK: / offline.html Browser Cache Browser cache is an automatic caching mechanism ... Read More