From the OpenReplay Blog
Handling Time in Tests: Reliable Patterns for Async and Delays
Fix flaky tests caused by timers and async timing in Jest, Vitest, React Testing Library, Playwright, and Cypress using reliable fake timer patterns.
10 Git Commands Every Developer Should Know
Ten essential Git commands including git switch, git restore, and git reflog explained so developers can manage daily workflows with confidence.
Smarter Caching in Next.js: Partial Rendering and Reusable Components
Next.js App Router caching across Data Cache, Full Route Cache, and Partial Prerendering becomes predictable when server components own their caching policy.
Automating Repetitive Tasks with Cron Jobs
Schedule scripts with cron jobs using correct syntax, absolute paths, logging, and overlap prevention, plus guidance on systemd timers and Kubernetes CronJobs.
Tips and Tricks for Debugging GitHub Actions
Fix failing CI/CD pipelines by enabling debug logging, validating workflows with actionlint, testing locally with nektos/act, and scoping artifacts correctly.
JavaScript Pitfalls: Five Issues You'll See Again and Again
Avoid JavaScript pitfalls like type coercion, this binding, hoisting, async misuse, and accidental mutation by recognizing patterns that break production code.
Running High-Performance Code with WASM
WebAssembly 3.0 brings GC, threads, Memory64, and SIMD to browsers. See how to structure WASM modules for high-performance frontend computation hotspots.
Comparing Electron and Tauri for Desktop Applications
Compare Electron and Tauri across performance, security, and bundle size to choose the right cross-platform desktop app framework for your next project.
Top 5 Image Placeholder Services for Web Developers
Compare five CDN-backed image placeholder services, including Placehold.co, Lorem Picsum, and DiceBear, to pick the right tool for modern frontend workflows.
Meet the JavaScript Engines Powering the Web
Compare V8, SpiderMonkey, JavaScriptCore, and Hermes to see how JavaScript engines parse, compile, and optimize code across browsers and runtimes.
Fixing 'Unexpected token < in JSON at position 0'
Fix the unexpected token < JSON parse error by diagnosing HTML responses caused by wrong URLs, auth redirects, or server errors in fetch and Next.js APIs.
A Developer's Guide to SSL Certificates
TLS certificates, ACME automation, and Let's Encrypt explained so developers can automate renewal and prevent certificate-related outages in production APIs.
Inspecting HTTPS Requests with HTTP Toolkit
HTTP Toolkit intercepts HTTPS traffic via a MITM proxy, exposing real request and response data for browsers, mobile apps, and desktop applications.
Three Alternatives to Vercel for Modern Web Hosting
Compare Netlify, Cloudflare Pages, and Fly.io as Vercel alternatives to choose the right edge hosting platform for your modern web projects.
The Strange Life of NaN in JavaScript
JavaScript NaN follows IEEE 754 rules that cause silent failures. Use Number.isNaN for detection and validate inputs before JSON serialization.
A Lightweight Approach to Tooltips in React
Compare native title, CSS-only patterns, custom hooks, and Floating UI to build accessible React tooltips with collision detection and minimal bundle size.
How to Migrate Your Tests from Enzyme to React Testing Library
Move from Enzyme to React Testing Library with refactoring patterns, accessible queries, and async handling for behavior-focused component tests.
Five ESLint Plugins That Improve Code Quality
Five ESLint plugins covering typescript-eslint, eslint-plugin-import, unicorn, jsx-a11y, and CSS linting help teams catch real bugs before production.
How to Create Custom Errors in JavaScript
Build custom JavaScript error classes with Error.cause, structured fields, and class syntax to identify and debug failures across async application flows.
A Beginner's Guide to Docker Images and Containers
Grasp Docker image and container basics, build Dockerfiles, manage volumes, and run multi-container frontend setups using Docker Compose with confidence.
Fix 'TypeError: Cannot Read Property of Undefined' in JavaScript
Fix JavaScript TypeError cannot read property of undefined with optional chaining, nullish coalescing, and React state initialization to stop runtime errors.
Customizing Your Editor with Better Coding Fonts
Compare Fira Code, JetBrains Mono, Cascadia Code, and Monaspace, then configure ligatures and Nerd Fonts in VS Code and JetBrains IDEs for better readability.
JavaScript Objects 101: The Building Blocks of Your Code
Build a solid grasp of JavaScript objects, prototype chains, and modern methods like Object.groupBy and Object.hasOwn to write efficient, maintainable code.
How to Add Social Login with BetterAuth
Add social login to TypeScript applications using BetterAuth, configure Google and GitHub providers, and extend OAuth2 support with the Generic OAuth plugin.