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Javascript
Dev
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Js interview #1 : var, let, and const in JavaScript – What's the Difference?
- JavaScript variables can be declared using var, let, or const, with differences in scope, hoisting, reassignment, and more.
- 1. Scope: var is function-scoped, while let and const are block-scoped.
- 2. Hoisting: var is hoisted and initialized, while let and const are hoisted but not initialized.
- 3. Redeclaration & Reassignment: var allows both redeclaration and reassignment, let allows reassignment but not redeclaration, and const allows neither.
- 4. Temporal Dead Zone (TDZ): Variables declared with let and const have a Temporal Dead Zone where they cannot be accessed before declaration.
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Dev
2w
172
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Tidbit 04: JavaScript Promise Chain vs No-Chain
- A promise chain is formed when multiple promise handler functions (.then() or .catch()) are appended to handle results and errors.
- In a promise chain, each handler function receives the result from the previous function, forming a seamless chain of operations.
- When the promise is not chained properly by prefixing the promise every time before each .then() handler, it results in independent promise handling and can lead to unexpected outcomes.
- Understanding how to correctly chain promises is crucial in JavaScript to ensure proper flow of asynchronous operations and avoid common mistakes developers make.
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Dev
2w
215
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JavaScript Data Structures: Managing Tasks with Arrays and Objects
- The article discusses managing tasks in JavaScript using arrays, objects, strings, operators, control flow, and loops to create a dynamic and interactive Task Manager.
- Arrays in JavaScript are ordered lists perfect for managing collections, with key methods like push, pop, shift, unshift, forEach, map, filter, and length.
- Spread operator (...) creates a shallow copy of arrays, while array destructuring unpacks array values into individual variables.
- JavaScript objects store structured data as key-value pairs, and useful methods include dot notation, bracket notation, destructuring, Object.keys, and Object.values.
- Strings in JavaScript manipulate text data, with methods like toLowerCase, toUpperCase, trim, includes, replace, split, startsWith, and endsWith.
- Operators in JavaScript cover arithmetic, comparison, and logical decisions, and control flow includes if-else statements, switch cases, and ternary operators.
- Loops in JavaScript include for loop, while loop, and modern for...of loop for processing lists of tasks efficiently.
- The article also showcases a project on building a Dynamic Task Manager using objects in an array, forEach loop for dynamic rendering, and priority-based styling.
- The project achieves structured task data storage, dynamic rendering with forEach, priority-based styling, and the addition of priority badges for enhanced visualization.
- This practical example demonstrates how to implement effective task management in JavaScript using various programming concepts for a more interactive user experience.
- The article concludes by hinting at introducing event handling and interactive task management in the upcoming chapter of the series.
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Speckyboy
2w
315
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8 CSS & JavaScript Snippets for Creating Sticky Elements
- Sticky design elements like headers and sidebars help users navigate long pages and maintain visibility of important features while scrolling.
- CSS provides a simple way to create sticky elements using the position property, while JavaScript can be used for more complex functionality.
- Various creative CSS and JavaScript snippets for implementing sticky elements were showcased on CodePen to enhance user experience.
- Examples included a pure CSS header animation, a responsive sidebar navigation, a sticky table header and column, and sticky sections for long scrolls.
- Other snippets featured multi-navigation sticky bars, a sticky video implementation, and a dynamic sticky sidebar component for shopping carts.
- These snippets demonstrate how sticky elements can be used beyond traditional navigation, offering creative and interactive ways to engage users.
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Dev
2w
259
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Scop in Javascript.
- JavaScript's scope is crucial in defining the reach of variables, functions, and objects in a codebase.
- Global scope allows accessibility across the entire program, irrespective of code blocks.
- Local scope confines entities to specific code blocks like if statements or loops.
- Function scope limits access to variables, functions, and objects within the specific function they are defined in.
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Dev
2w
358
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Asynchronous programming in Javascript
- JavaScript offers asynchronous programming to handle tasks efficiently while waiting for asynchronous operations to complete.
- Callback functions are used in asynchronous programming to execute tasks after the main function has been completed.
- Promises in JavaScript represent the result of an asynchronous operation, allowing developers to handle asynchronous tasks more elegantly.
- Async/await is the latest and readable way to handle asynchronous operations in JavaScript, making the code look synchronous for better maintainability.
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Dev
2w
0
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Understanding Type Coercion in JavaScript
- Type coercion in JavaScript refers to the automatic or implicit conversion of one data type to another.
- JavaScript performs type coercion when trying to make sense of different types being used together, in scenarios like adding a number to a string or using loose equality (==) for comparisons.
- There are two types of coercion - Implicit Coercion, where JavaScript automatically converts types, and Explicit Coercion, where types are manually converted using functions like Number(), String(), and Boolean().
- Understanding type coercion is essential to write cleaner code and avoid bugs, with best practices like using strict equality (===) over loose equality (==), converting values explicitly, handling falsy values carefully, and refraining from comparing complex types like arrays or objects directly.
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Medium
2w
207
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Capturing Live User Input with JavaScript Input Events
- Real-time input feedback relies on browsers and scripts understanding when to trigger and react to input events effectively.
- The input event reacts instantly to every small change in a field's value, perfect for reflecting changes immediately.
- In contrast, the change event triggers only when the field loses focus and its value has changed, waiting for user commitment.
- Browsers queue input events in the main thread, allowing multiple listeners to fire consecutively with the already updated field value.
- Different input types, like text fields, sliders, checkboxes, and dropdowns, trigger input and change events in varying patterns.
- Managing a stream of input events can lead to performance issues, which can be addressed using throttling and debouncing patterns to control the frequency of function execution.
- Throttling limits how often a function runs by responding at fixed time intervals, preventing overwhelming browser or server operations.
- Debouncing waits for a pause in input before executing the function, ideal for scenarios where response after the user finishes typing is desired.
- Throttling provides frequent updates while input is ongoing, while debounce ensures a single callback after a period of inactivity.
- Understanding and implementing throttling and debouncing appropriately can enhance user experience by managing input event handling effectively.
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Dev
2w
394
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Advanced Integration of JavaScript with Native Code via FFI
- JavaScript's evolution has led to the integration of Foreign Function Interface (FFI) for interfacing with native code, enabling performance-critical features and interaction with system resources.
- FFI allows JavaScript to call functions and manipulate data types from languages like C, C++, and Rust, aiding in enhancing application capabilities while optimizing performance.
- Popular runtimes like Node.js support FFI through N-API or node-addon-api, WebAssembly interfaces, and lightweight embedded engines such as Duktape and QuickJS.
- Integration of native addons in Node.js entails creating C++ addons, setting up the environment, writing C++ code, defining projects using binding.gyp, building the addon, and using it in JavaScript.
- WebAssembly offers an alternative FFI method by compiling C/C++ code for JavaScript execution, providing portability across platforms for cross-platform applications.
- Challenges with FFI include memory management, type conversions, handling callbacks, and optimizing asynchronous operations between JavaScript and native code.
- FFI's performance considerations involve minimizing data transfer, utilizing worker threads, and profiling critical paths for optimization using DevTools and profilers.
- Real-world applications of FFI include machine learning libraries, game development for high-performance graphics, and video processing tasks requiring high-performance computing.
- Debugging techniques involve preventing crashes, integrating debugging tools like gdb, and rigorous testing of edge cases in JavaScript and native contexts.
- Performance enhancements and capabilities in applications can be achieved by mastering FFI, understanding its workings, and addressing potential pitfalls for robust and efficient development.
- Further exploration through Node.js N-API, Emscripten for WebAssembly, and resources like 'Mastering Node.js: Advanced Patterns' can deepen understanding of FFI integration.
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Medium
2w
142
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Module vs CommonJS in JavaScript: A Comprehensive Comparison
- Modules in JavaScript allow developers to break down code into reusable, self-contained units, with each module encapsulating its own scope.
- JavaScript supports two primary module systems: CommonJS and ES Modules (ESM).
- While CommonJS is synchronous and widely used in older Node.js projects, ES Modules (ESM) are asynchronous, support static analysis, and work in both browsers and Node.js (Node.js 12 onwards).
- ES Modules are the standardized, modern approach preferred for new projects due to features like browser support, tree shaking, and asynchronous loading. However, CommonJS remains relevant for legacy Node.js projects.
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Medium
2w
633
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JavaScript: The “Slow” Language That Actually Runs Fast
- JavaScript has a contradictory reputation - powering websites efficiently while being perceived as slow by some developers.
- The language was created in just 10 days in 1995, intended as a lightweight scripting language for web browsers, with its expanded usage beyond that not initially foreseen.
- Despite not being built for performance, JavaScript can be optimized for speed through the right mindset, tools, and coding patterns.
- Developers can enhance JavaScript performance by employing efficient practices to overcome its initial limitations.
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Dev
2w
316
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Scop in Javascript with example
- JavaScript is a powerful programming language widely used for web development with scope as a key concept.
- Global scope allows access to variables, functions, and objects from anywhere within the program.
- Local scope restricts access to variables, functions, and objects within a specific block of code.
- Function scope limits access to variables, functions, and objects within a specific function.
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Dev
2w
403
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Daily JavaScript Challenge #JS-201: Check for Balanced Parentheses
- Today's JavaScript challenge revolves around checking for balanced parentheses in a given string.
- A valid string is one where every opening parenthesis is correctly matched with a corresponding closing parenthesis, and they are properly nested.
- Developers are encouraged to fork the challenge, write their solutions, test them, and share their approaches in the comments.
- The challenge aims to help programmers enhance their string manipulation skills in JavaScript.
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Medium
2w
60
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Timing Animation Loops with requestAnimationFrame in JavaScript
- Animations appear smooth when timed to sync with screen redraws that typically happen 60 times per second using requestAnimationFrame in JavaScript.
- requestAnimationFrame schedules animation code to run just before the next frame is shown, ensuring fluid motion and avoiding stuttering.
- The cycle of website frame processing includes JavaScript work, layout changes, paint, fitting within the window between screen refreshes.
- Using requestAnimationFrame, animations need to align with the window of time between screen refreshes to avoid lag or jumpiness in motion.
- The callback passed to requestAnimationFrame runs at the browser's scheduled time, maintaining synchronization with screen updates.
- requestAnimationFrame adjusts timing automatically based on display refresh rates, ensuring smoother animations without the need for manual adjustments.
- Callbacks with requestAnimationFrame run one per frame, preventing flooding of updates and ensuring everything stays in sync with screen rendering.
- Compared to setInterval or setTimeout, requestAnimationFrame better aligns with screen refreshes for more natural-looking animations.
- The timestamp provided by requestAnimationFrame can be used to control animation speed and adjust motion based on elapsed time.
- By calling requestAnimationFrame within the callback, a loop is created to continue the animation frame by frame, ensuring precise control over timing.
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Dev
2w
21
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Mastering JavaScript Date Formatting: From Native Methods to Modern Libraries
- Date formatting in JavaScript is crucial for displaying dates in a human-readable format across different scenarios.
- Challenges like locale differences, time zones, browser inconsistencies, and manual string manipulation can be mitigated using modern JavaScript tools.
- Built-in JavaScript APIs like Date.toString(), toUTCString(), and toISOString() provide quick ways to handle date formatting.
- Date.toLocaleDateString() and toLocaleTimeString() allow customization for displaying dates in the user's locale.
- Intl.DateTimeFormat offers more control over formatting and time zones, enhancing performance and accuracy.
- Manual formatting with template literals can be done for custom date formats not covered by built-in APIs.
- Third-party libraries like date-fns, Moment.js, and Luxon provide advanced features for date formatting, parsing, and manipulation.
- Best practices include storing dates in UTC, handling time zones explicitly, and automating unit testing for date-related logic.
- Examples show how to create custom date widgets, implement time ago functionality, and parse user input for reformatting dates.
- Resources like MDN, ECMAScript Intl API, date-fns documentation, Luxon documentation, and timeago.js offer further reading for mastering JavaScript date formatting.
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