Posted inLibraries: React
How to create a React component
High-quality reusable components are defined by purity, clarity, robustness, and generalization. Discover best practices for component design and testing.
Posted inObjects and Prototypes
How to create an object in JavaScript
In JavaScript, object literals provide a convenient way to create objects using a simple syntax.…
Posted inUnit Testing: Jest
How to install and configure Jest
Optimize testing performance with test doubles to isolate code from slow dependencies. Identify "seams" in your application for efficient behavior alteration. Use mock implementations to eliminate delays caused by database queries, enhancing the speed and reliability of unit tests. Balance isolation and integration testing for effective results.
Posted inCallbacks and Event Loop
How to define a callback function in JavaScript
Asynchronous JavaScript operations rely heavily on callbacks, especially in single-threaded environments. Callbacks enable non-blocking execution during tasks like network requests and file reading. However, nested callbacks can lead to "callback hell." Promises and async/await provide clearer, more manageable code structures, simplifying error handling and improving readability.
Posted inNode.js Core
How to create a module in Node.js
Navigating the balance between functions and objects in programming is crucial for maintainable code. Pure functions offer predictability and testability, while objects manage complex state effectively. Avoid 'ugly' patterns like global mutations or anemic domain models. Choosing the right approach enhances code architecture and discipline.
Posted inAsynchronous JavaScript
How to run code asynchronously in JavaScript
Mastering asynchronous programming involves tackling challenges like race conditions and callback hell. Implementing design patterns such as Promise.all and event-driven architectures enhances code structure and maintainability. Learn how to efficiently handle multiple asynchronous operations while reducing complexity for cleaner applications.
Posted inPromises and Async-Await
How to resolve a promise in JavaScript
JavaScript async/await for cleaner asynchronous code. Syntactic sugar over Promises to replace promise chains and callback hell. Write non-blocking, synchronous-style logic with async functions and the await keyword. Unifies asynchronous error handling with standard try...catch blocks.
Posted inError Handling
How to handle errors in JavaScript using try and catch
Parsing error.message in JavaScript is a fragile anti-pattern. For robust error handling, use custom error classes extending Error. Check error types in a catch block with instanceof for NetworkError or ValidationError. A type-safe, stable alternative to string inspection.
Posted inClasses and Inheritance
How to define a class in JavaScript
JavaScript class inheritance uses the extends keyword for subclasses. The super() function calls the parent constructor, inheriting properties. Subclasses can override methods for polymorphism or call parent methods with super.methodName(). This system is based on prototype-based inheritance.
Posted inStandard Objects: Math
How to use the Math object in JavaScript
JavaScript Math functions: Math.max() & Math.min() on arrays using spread syntax to avoid NaN. Generate random integers in a range with Math.random(). Core functions: Math.abs(), Math.pow(), Math.sqrt(). Security warning: Math.random() is not cryptographically secure.