JS FAQ - JavaScript Guides Online

How to send a GET request with Axios in JavaScript

Graceful Axios error handling using the error object (`error.response`, `error.request`). Manage HTTP status codes with `validateStatus`, set request timeouts, and cancel in-flight requests with an `AbortController` signal.

Canvas and WebGL

How to draw a rectangle on canvas in JavaScript

Canvas and WebGL2d context, canvas, draw, js graphics

Transforming shapes on the canvas involves rotation and scaling through methods like `rotate()`, `scale()`, and `translate()`. To rotate a shape around its center, translate the canvas origin, apply rotation, and draw relative to the new origin. Use `beginPath()` for custom shapes and manage image loading with `drawImage()` for asynchronous rendering.

Event Loop Internals

How to explain the event loop in JavaScript

Event Loop Internalsasync, event loop, explanation, overview

JavaScript event loop, call stack, and browser repaints. Long-running synchronous tasks causing a frozen UI. Analysis of macrotasks vs. microtasks, using setTimeout and Promises for non-blocking code and immediate user feedback. Debugging asynchronous execution order.

DOM Manipulation

How to select an element by ID in JavaScript

DOM Manipulationdom, getElementById, js dom, selector

Managing unique HTML element IDs in JavaScript to prevent `getElementById` bugs. Use consistent naming conventions and dynamic ID generation for reusable components to avoid duplicate IDs. For element groups, use a `class` with `querySelectorAll` instead.

Standard Objects: RegExp

How to create a regular expression in JavaScript

Standard Objects: RegExpjs regexp, pattern, regex, regexp

Master regular expressions in JavaScript to validate and manipulate strings. Learn syntax, anchors, quantifiers, and advanced matching techniques.

Testing Frameworks

How to write your first test in JavaScript

Testing Frameworksbasics, testing, unit test

Pragmatic software testing strategy focusing on boundaries and edge cases over 100% code coverage. Test the happy path, then find real bugs in tricky spots for code confidence. Includes examples like a string truncation function.

Promises and Async-Await

How to reject a promise in JavaScript

Promises and Async-Awaiterror, js promises, promise, reject

Avoid the cardinal sin of error handling in JavaScript: throwing strings. Instead, use `throw new Error()` for better debugging. Strings lack context, leading to confusion and ineffective logging. An `Error` object provides essential properties like `message` and `stack`, crucial for tracking issues. Prioritize clean, professional coding practices.

Code Quality: ESLint/Prettier

How to configure ESLint rules

Code Quality: ESLint/Prettierconfig, customize, eslint, rules

ESLint configuration using the `extends` property to inherit a recommended base ruleset like `eslint:recommended`. Build on a shared community standard, a sane foundation for project-specific rules. This strategic choice catches common bugs and errors, avoiding a ruleset built from scratch.

Fetch API and AJAX

How to make a GET request with fetch in JavaScript

Fetch API and AJAXfetch, get, http request, js fetch

Optimize your JavaScript network requests with a custom `apiFetch` function. Simplify error handling, response parsing, and logging in one reusable wrapper. Incorporate `async/await` for cleaner code and implement `AbortController` for timeout management. Avoid repetitive boilerplate and enhance application reliability seamlessly.

Event Handling

How to add a click event listener in JavaScript

Event Handlingclick, events, js events, listener

Efficient click event management in complex applications requires robust patterns like event delegation, which reduces active listeners and enhances performance. Essential practices include diligent cleanup of listeners to prevent memory leaks, using debouncing to optimize heavy operations, and ensuring accessibility for keyboard navigation.