标签：#react

We live in an era where our most intimate data—heart rates, sleep cycles, and step counts—is constantly uploaded to the cloud for "analysis." But what if you could have a world-class AI medical assistant living entirely on your device? Today, we are pushing the boundaries of Edge AI and Privacy-preserving machine learning by deploying a quantized Llama-3 model directly onto an iPhone using MLC-LLM . By leveraging Apple HealthKit and hardware acceleration via Metal , we can transform "Pixels and Pulses" into actionable insights without a single byte leaving the device. This tutorial dives deep into the architecture of on-device LLMs, specifically focusing on how to bridge the gap between high-performance C++ runtimes and a React Native UI. If you're interested in more advanced patterns for production-grade AI integration, be sure to explore the engineering deep-dives at the WellAlly Blog , which served as a massive inspiration for this architecture. 🚀 The Architecture: Why On-Device? The challenge with running Llama-3 on mobile isn't just memory—it's the data pipeline. We need to fetch sensitive data from HealthKit, format it into a prompt, and run inference using the phone's GPU. System Data Flow graph TD A[User Query: How was my sleep?] --> B[React Native UI] B --> C{Swift Bridge} C --> D[Apple HealthKit API] D --> E[Health Data Context] E --> F[MLC-LLM Engine] G[Quantized Llama-3 Weights] --> F F --> H[On-Device Inference via Metal] H --> I[AI Generated Health Report] I --> B 🛠 Prerequisites MLC-LLM : Our compiler stack for universal LLM deployment. TVM (Tensor Virtual Machine) : The backbone for hardware acceleration. React Native : For the cross-platform UI. Xcode & Swift : To interface with Apple's HealthKit. Llama-3-8B-Instruct (Quantized) : We'll use 4-bit quantization (q4f16_1) to fit within mobile RAM limits. Step 1: Quantizing Llama-3 for Mobile Standard Llama-3 is too heavy for a phone. We use the MLC-LLM CLI to compile the model into a format that the iP

Every time I added AI to a React app, I rewrote the same 200+ lines. Streaming loop. Manual message history. Tool call orchestration. Error handling. setIsLoading(false) only if I remembered. After the third project I stopped and asked: why is nobody solving this the way RTK Query solved REST APIs? So I built Strand ( https://github.com/strand-js/strand ). Before const [messages, setMessages] = useState([]) const [isLoading, setIsLoading] = useState(false) async function send(text) { setIsLoading(true) manually stream tokens manually detect tool calls manually loop until done setIsLoading(false) only if you remembered } After const { messages, send, isPending, isStreaming, cancel } = useConversation({ system: 'You are a helpful assistant.', }) Streaming, history, tool calls, cancellation, retry; all handled. The thing nobody else has: useToolCall Works from ANY component; no prop drilling function WeatherStatus() { const { status, input, output } = useToolCall('get_weather') if (status === 'running') return <div>Checking {input?.location}…</div> if (status === 'done') return <div>{output?.temp}°F</div> return null } Live tool state: pending → running → done. Its observable anywhere in your tree. Fixing the isLoading design flaw The Vercel AI SDK has 4+ open issues ( https://github.com/vercel/ai/issues ) about isLoading getting stuck. The reason is architectural because "request sent" and "tokens arriving" are different states. Strand tracks four: const { isPending, isStreaming, isDone, error } = useConversation() // isPending: waiting for first token // isStreaming: tokens arriving // isDone: just completed // error: something failed Works with Anthropic, OpenAI, and Google Gemini npm install @strand-js/core @strand-js/react zod npm install @strand-js/anthropic # or openai, or google Swap providers by changing one server import. Zero frontend changes. v0.1.8, MIT, open source. → https://github.com/strand-js/strand

React Server Components in 2026: Patterns, Pitfalls, and When to Actually Use Them Most React Server Components problems stem from teams treating them like regular components with a new rendering location. The architecture shift is deeper than that. RSC fundamentally changes where code executes, what data can cross boundaries, and how developers reason about state. Teams that ignore these constraints burn weeks debugging serialization errors and performance regressions. The pattern that production teams overlook is the server/client boundary itself. Understanding where computation happens, what props can serialize, and when to break out of server rendering determines whether RSC improves or destroys your application's performance. Core Concepts: How RSC Actually Works Under the Hood React Server Components execute on the server and send rendered output to the client. No JavaScript bundle ships for these components. The client receives a serialized tree describing what to render, along with holes for client components to fill. The execution model works like this: the server runs your component tree, fetches data directly, and serializes the result. When the payload reaches the browser, React reconstructs the UI without hydrating server component code. Only client components hydrate with their JavaScript bundles. RSC execution flow from server to client This distinction is critical. Server components cannot use hooks like useState or useEffect because they don't exist in the browser. They render once on the server per request. Client components ship JavaScript and can use the full React API. The implication here is that your component tree becomes a mix of server and client code. The boundary between them determines your bundle size, waterfall depth, and debugging complexity. Production-Ready Patterns: Streaming, Suspense, and Data Fetching The correct pattern for data fetching in server components eliminates the request waterfall. Fetch data directly in the component

Learn how to organize React projects for scalability, maintainability, and team collaboration. Introduction As React applications grow, one challenge consistently emerges: project organization . A folder structure that works perfectly for a small side project can quickly become a nightmare when multiple developers contribute to a production-scale application. Whether you're a junior React developer preparing for interviews, a mid-level frontend engineer looking to improve code maintainability, or a technical recruiter trying to understand modern React development practices, understanding scalable React folder structures is essential. In this guide, we'll explore the most popular React folder organization strategies, their pros and cons, and the structure many modern engineering teams use to build scalable applications. Why React Folder Structure Matters A well-organized React project provides several benefits: Faster onboarding for new developers Easier code maintenance Better scalability as features grow Reduced code duplication Improved team collaboration Cleaner separation of concerns Many React applications start simple: src/ ├── App.jsx ├── Home.jsx ├── Login.jsx └── Dashboard.jsx This works initially, but as the project grows to dozens or hundreds of components, finding and maintaining files becomes increasingly difficult. Common React Folder Structure Approaches 1. Type-Based Folder Structure One of the earliest and most common approaches is organizing files by their type. src/ ├── components/ ├── pages/ ├── hooks/ ├── services/ ├── utils/ ├── assets/ └── contexts/ Advantages Easy to understand Suitable for small projects Quick setup Disadvantages Components folder can become enormous Related files are spread across multiple directories Harder to maintain in large teams For example, a user profile feature might have files located in: components/UserProfile.jsx hooks/useUser.js services/userService.js pages/ProfilePage.jsx Finding all files related to one feat

Your password bar goes from "weak" to "strong" when you add characters. Have you ever wondered how React 'remembers' your inputs? 'State' is your answer. A state remembers what input you added. Assume you are typing your name "John", initial state is the blank slate (starting value, like empty input, counter at zero, or an empty whiteboard) in the input bar, whenever you add a new letter, a function named 'setState' is called to change the state from "" (empty input bar) to "J", then again to "Jo", again to "Joh", etc... And following the setState, React automatically re-renders the UI. Think of re-rendering as erasing everything and re-writing the UI with the new state. Initial state was "", then setState updates it from "" to "J". Following that, React automatically erases the first UI and then it will build a new UI with the new state. Why not just use a variable? You might be thinking, "Why don't just use variables and change them whenever you want it?", and you might do that, but the value only changes in your codebase, but the UI will still show the first value. (and that defeated the purpose) What is [state, setState] concept? const [state, setState] = useState('placeholder') is the basic syntax. useState provides an array of ['current-state', 'function to change state']. It is destructured to the two values (state = 'current-state' and setState = 'function to change state'). When you enter an input, the function is called and the 'current-state' will be updated to the 'new-state'. How to use it To use useState follow these two simple steps: Import useState from 'react' import { useState } from 'react'; Declare it (for example to input age): const [age, setAge] = useState(20); where, 'age' is current state. 'setAge' is the function that will create the new state. 20 is the placeholder. Now try it yourself! Open your React project and add a counter using useState. Watch the UI update every time you click.

The next attempt was the standard Maps URL: window . open ( `https://maps.google.com/maps?daddr= ${ lat } , ${ lng } ` , ' _blank ' ); This opens Maps, but in the browser — not the app. And it shows the route preview, not turn-by-turn navigation. What worked: Android Intent URLs Android supports a special URL scheme that tells Chrome to launch a native app directly: window . location . href = `intent://navigation/now?ll= ${ lat } , ${ lng } &title=Next+stop#Intent;scheme=google.navigation;package=com.google.android.apps.maps;end` ; Breaking it down: intent:// — tells Chrome this is an Android intent navigation/now?ll=${lat},${lng} — opens Maps in navigation mode, starting immediately #Intent;scheme=google.navigation — the URI scheme to use package=com.google.android.apps.maps — the target app package end — closes the intent syntax This opens the Google Maps app directly and starts turn-by-turn navigation automatically — no extra taps needed. It also works with Android Auto. The full function export function openNavigation ( destination : { lat : number ; lng : number }): void { window . location . href = `intent://navigation/now?ll= ${ destination . lat } , ${ destination . lng } &title=Next+stop#Intent;scheme=google.navigation;package=com.google.android.apps.maps;end` ; } Call it on any user gesture (tap, click) and it works without being blocked by the browser. The app The full PWA is open source if you want to see the context: 🔗 GitHub repo 🌐 Live app Built with React + TypeScript + Vite + Dexie.js + @vis .gl/react-google-maps. If you're building a PWA that needs to hand off to Google Maps navigation on Android, this intent URL is the cleanest solution I found. Hope it saves you the hour I spent figuring it out.

Ekehi platform has moved from hand-written HTML/CSS/JS pages to a typed, component-driven React 19 client and a module-based TypeScript Express/Node.js API. 0. Where we started and where we landed Before. A static client built from per-page folders ( landing/ , contributors/ , login/ , signup/ , admin/ ), each shipping its own index.html , a shared styles.css , and vanilla ES module scripts under client/shared/ . The server was an Express API written in plain JavaScript. After. Layer Before After Client Static HTML + CSS + vanilla JS React 19 + Vite 8 + TanStack Router + TypeScript 6 Styling One global styles.css Tailwind CSS 4 with @theme design tokens Data fetch scattered per page TanStack Query over a typed lib/api client Server Express in JavaScript Express + TypeScript, module-per-domain Repo Two loose folders pnpm workspace with shared git hooks Quality gate None ESLint 9, Prettier 3, Husky, commitlint, Vitest The migration ran in two phases on separate branches: **Phase 1 — client rewrite. **Phase 2 — server rewrite. 1. Why this framework? Choice: React 19 , rendered as a client-side SPA through Vite 8 , routed by TanStack Router . TanStack Router was chosen rather than React Router because it gives fully type-safe routes, first-class search-param typing, built-in code-splitting, and file-based route generation that pairs cleanly with Vite. 2. The folder and component structure The client uses a feature-sliced layout: code is grouped by domain, not by technical type. client/src/ ├── components/ │ ├── layout/ navbar.tsx, footer.tsx │ └── ui/ button, input, modal, select, dropdown, ... (design system) ├── config/ env.ts, env-schema.ts, endpoints.ts ├── features/ one folder per domain │ ├── auth/ auth.query.ts, auth.service.ts, auth.types.ts, components/, pages/ │ ├── opportunities/ pages/ │ ├── resources/ pages/ │ ├── submissions/ pages/ │ ├── admin/ pages/ │ └── site/ pages/ (landing, contributors) ├── lib/ │ ├── api/ request.ts, errors.ts, refresh.ts, types.t

Modern collaboration needs more than documents and chat messages. Teams need a shared visual space where ideas can be created, organized, and refined together in real time. That's why I built SyncCanvas — an AI-powered collaborative whiteboard that combines real-time multiplayer collaboration, infinite canvas drawing, and AI-assisted brainstorming into one modern workspace. The Problem Most collaboration tools focus on only one aspect of teamwork. Some are great for drawing. Others are excellent for documentation. AI tools often live in separate windows, disconnected from the creative workflow. I wanted a platform where teams could brainstorm visually while AI actively helped generate and organize ideas directly on the canvas. Introducing SyncCanvas SyncCanvas is an infinite multiplayer whiteboard designed for students, developers, teams, and creators. Key features include: Real-time collaboration with live synchronization Infinite canvas with pan and zoom Drawing tools, shapes, text, and sticky notes AI-powered content generation using Gemini Private room sharing Guest mode access PNG export support WiFi Rooms for local collaboration Real-Time Collaboration Collaboration is at the heart of SyncCanvas. Using Yjs and WebSockets, multiple users can work on the same board simultaneously while seeing updates instantly. Users can: View live cursors Track online participants Join private rooms using secure room codes Collaborate anonymously through guest mode This creates a seamless experience similar to working together in the same room. Infinite Canvas Experience The whiteboard is designed to be limitless. Users can: Draw freehand sketches Create rectangles and circles Add text elements Organize ideas with sticky notes Move freely across an infinite workspace Export workspaces as images The canvas is powered by Fabric.js, providing smooth rendering and flexibility for future enhancements. AI-Powered Brainstorming One of the most exciting features is the integration of G

TSRX is a TypeScript language extension developed by Dominic Gannaway, designed to build declarative user interfaces in a framework-agnostic manner. It compiles single .tsrx files to various runtime targets and supports scoped styles and declarative error handling. TSRX is currently in alpha and is open source under the MIT license. By Daniel Curtis

If you've ever tried to build a trading dashboard, a crypto portfolio tracker, or any financial app, you probably ran into the "charting problem" pretty quickly. The standard industry approach goes something like this: Embed a heavy <iframe> from a 3rd party provider. Realize it doesn't quite match your app's UI/theme. Struggle with limited postMessage APIs to push real-time data. Watch the UI lag when you try to render multiple charts on the same page. I got tired of fighting with iframe embeds and DOM-based SVG charts that couldn't handle thousands of real-time ticks. I needed something native, fast, and entirely under my control. So, I built one. And today, I'm fully open-sourcing the core engine. Meet Exeria Charts Exeria Charts is a source-available, high-performance financial charting library designed for self-hosted web applications. Instead of embedding external widgets, Exeria renders directly inside your application using a highly optimized Canvas architecture. Here’s a quick look at what it can do: https://exeria.dev The Tech Constraints (Why build another charting lib?) Building a financial chart isn't just about drawing boxes and lines. It’s about performance under pressure. When designing the architecture, we had a few strict requirements: Zero iframes: It had to be a native JavaScript/React module that lives in the main DOM tree, styled perfectly to match the host application. High-frequency updates: Crypto and forex markets move fast. The library needed to handle sub-millisecond tick updates without dropping frames or blocking the main UI thread. Unified runtime: I didn't want a separate library for line charts, another for candlesticks, and another for volume histograms. We needed one engine that could switch views instantly. How to use it We designed the API to be as straightforward as possible. Here is what a vanilla JS implementation looks like: import { createChart } from " @efixdata/exeria-chart " ; // 1. Grab your container const container = d

Hi everyone 👋 I'm a Full Stack Developer with experience in JavaScript, React.js, Next.js, Node.js, Express.js, MongoDB, and WordPress development. Over the last few years, I have worked on multiple projects ranging from company websites to full-stack web applications. In this article, I want to share my experience transitioning from the traditional MERN stack to Next.js and why it has become my preferred framework for modern web development. Why I Started with MERN Stack The MERN stack was my first choice because it allowed me to build complete applications using JavaScript. Technologies MongoDB Express.js React.js Node.js Benefits ✅ Single language across frontend and backend ✅ Huge ecosystem ✅ Fast development ✅ Easy API integration Challenges I Faced As projects became larger, I started facing issues like: SEO limitations Performance optimization Routing complexity Code organization Server-side rendering requirements This is where Next.js entered the picture. Why I Switched to Next.js Next.js provides several powerful features out of the box. Server-Side Rendering (SSR) Pages can be rendered on the server which improves SEO and initial page load performance. 2.** Static Site Generation (SSG)** Perfect for blogs, landing pages, and marketing websites. 3.** App Router** The new App Router makes routing cleaner and more scalable. Server Components Less JavaScript is sent to the browser, improving performance. Better Developer Experience Features like: File-based routing Built-in image optimization Middleware API routes make development faster and cleaner. My Current Tech Stack Frontend Next.js React.js TypeScript Tailwind CSS Backend Node.js Express.js MongoDB Tools Git & GitHub Postman Vercel Contentful CMS What I Learned The biggest lesson I learned is: Focus on solving real business problems instead of chasing every new technology. Frameworks will change, but understanding JavaScript fundamentals, APIs, databases, authentication, and system design will always be

Expo SDK 56 ships with a custom Kotlin compiler plugin that eliminates reflection from Expo Modules on Android. The result: 70% faster module initialization and a 30% reduction in time to first render. The plugin runs during compilation, so app developers get these performance gains automatically without changing any code. Module authors can unlock even bigger wins with a single annotation. This post walks through how we built it and why this approach succeeded where previous attempts failed. For the Swift side where we now talk to JSI directly, check out our companion post Talking to JSI in Swift . The reflection problem we inherited Before Expo Modules, we had Unimodules. They worked like old React Native bridge modules: you'd sprinkle annotations across methods you wanted to expose, and the runtime would discover everything through reflection. class ClipboardModule ( context : Context ) : ExportedModule ( context ) { override fun getName () = "ExpoClipboard" @ExpoMethod fun getStringAsync ( promise : Promise ) { val clip = clipboardManager . primaryClip ?. getItemAt ( 0 ) promise . resolve ( clip ?. text ?. toString () ?: "" ) } @ExpoMethod fun setStringAsync ( content : String , promise : Promise ) { clipboardManager . setPrimaryClip ( ClipData . newPlainText ( null , content )) promise . resolve ( true ) } } Reflection made sense when we needed metadata about our own code. What methods does this module export? What arguments do they accept? The JVM could answer those questions. But reflection costs time, and on Android that time comes straight out of your startup budget. Every module the runtime introspects adds milliseconds before users see your app. Building the Expo Modules API gave us a chance to fix this. We wanted better ergonomics and less reflection. The Kotlin DSL delivered both in one move, removing most reflection while making modules easier to write. But we couldn't eliminate all of it. Type information for function arguments and Record properties s

How we built a medicine-substitution engine that refuses to be clever There is a category of bugs where the code looks perfectly correct in code review, the unit tests pass, the demo on stage goes beautifully, and a real person dies. Medicine substitution is one of them. We built Agada — point a phone camera at a medicine strip in India, and the app tells you whether the drug is registered with the regulator, what it does, and whether a chemically identical version is available at the government pharmacy for a fraction of the price. The point is real: Indians spend about ₹65,000 crore a year out of pocket on branded medicines when the same molecule sits in a Jan Aushadhi Kendra at a tenth of the cost. The Dolo-650 story (₹32 vs ₹4.90 for the same paracetamol) is the most famous example, not the only one. The hard part isn't the camera, the OCR, or the price lookup. The hard part is the substitution engine — the piece of code that decides "is this salt the same as that salt." Get that wrong in the wrong direction, and the app cheerfully tells a user that their 500mg anti-epileptic can be replaced with a 200mg one, because the strings look similar. So we built a matcher that refuses to be clever. This post is about the parts we deleted. The starting problem A user scans "Crocin 500mg Tablet IP". A Jan Aushadhi record says "Paracetamol 500 mg". A naive matcher says: both contain "500", both contain "Paracetamol" (or "Acetaminophen", which is the same thing in a different country), ship it. The user buys the generic. Savings: ₹20. Everyone wins. Now consider: Crocin 650 Advance vs Dolo 650 — same molecule, same dose, different brands. Fine. Augmentin 625 vs Augmentin 375 — same two salts, different ratio. The combo tolerance might let it through, but the clinical implication is real. Levofloxacin 500 vs Ofloxacin 400 — both fluoroquinolones, both "similar," but levofloxacin is the levo-isomer of ofloxacin and is dosed at roughly half. A "fuzzy" match here could halve so

Prologue A while ago, I decided to develop a fully accessible main navigation component in React and write a series of articles documenting the steps it took to create a non-trivial accessible component. My last development article completed the base requirements for keyboard functionality within the component; attention now shifts to adding some of the last functionality required, closing sublists when the lists holding them now close and determining what happens when a closed component is entered via the keyboard through the Tab and Shift+Tab keys. Note : This article is one of a series demonstrating building a React navigational component from scratch while considering accessibility through the process. The articles are accompanied by a GitHub repository with releases tied to one or more articles; each builds on the previous one until a fully implemented navigation component is complete. Each release and its associated tag contain fully runnable code for the article. The code discussed in this article is available in the release. and may be downloaded at release 0.8.0 . Links in the article will take you to the proper file in the tagged GitHub Repository. Because the code for this release is scattered, line numbers are added to make it easier to locate in the linked GitHub file. Line numbers are also provided for those who would like to follow along with a downloaded copy. While code examples are written in JavaScript for brevity, all actual code is written in Typescript and targets React 19.x, all while using vanilla CSS. Examples use Next.js v16.x, which is not required to run the navigation component. You can view the requirements for the Focus and Refinement Support Release along with previous requirements. Content Links Introduction Acceptance Criteria Entering Closings Setting Up For Success Introduction The implementation of keyboard handling left one obvious keyboard issue to fix: an apparent keyboard trap that occurs when focus shifts into the component

android doze kills your background tasks and nobody explains why properly been building a react native app that schedules stuff to run later. worked fine every time i tested it. shipped it, and it started missing schedules. only when the phone had been sitting idle for a while. never on my desk. took me way too long to figure out what was going on so writing it up here. what happens you schedule something for 1am. check logs next morning: 01:00:00 alarm fired 01:00:02 connected (while back grounded, 2 seconds) 01:18:xx the actual send ran the connection came up fine. in 2 seconds. while the phone was back grounded. but the code that was supposed to do something with that connection ran 18 minutes later when something else woke the phone up. why doze mode freezes javascript timers. setTimeout, setInterval, any polling loop on the js thread-all frozen. but native events (connection callbacks, lifecycle events, native module bridges) keep firing. i had a setInterval checking "are we connected yet" every second. doze froze that loop. the connection came up, nobody noticed for 18 minutes because the thing checking for it was asleep. the phone could do the work. my code just couldn't tell. stuff i tried that didn't fix it foreground service — keeps the process alive but doesn't unfreeze js timers. not the problem. more setTimeout/setInterval variations, literally the thing causing it. spent two days making the problem worse. HeadlessJS dropped in without changes compiled, never ran on newer RN. lost a few hours there. the actual fix move everything off timers. put your work directly in the event handler. instead of polling to check if you're connected: js // this is frozen by doze. don't. setInterval (() => { if ( isReady ()) doWork () }, 1000 ) do this : jsconnection . on ( ' status ' , ( state ) => { if ( state === ' connected ' ) { doWork ( job ) } }) native events survive doze. timers don't. that's the whole thing. for waking up at the right time — native AlarmManager

I built a browser-based desktop environment (IP Linux) with React, TypeScript and Vite I have been working on a project called IP Linux : a browser-based desktop environment that runs as a static web app. Live site: https://ip-os-linux.vercel.app/ GitHub Repository: https://github.com/ikerperez12/IP-OS-LINUX It is not a real Linux distribution, and it does not run native binaries. The idea is different: I wanted to explore how far a polished desktop-like experience can go inside a normal browser tab. The result is a small web OS-style environment with: A splash / entry screen A desktop with icons, folders, and widgets A top panel with system controls A dock and app launcher Resizable and draggable windows Virtual workspaces Snap assist A global search / Spotlight-style command palette Local-first apps (Files, Terminal, settings, player) Reactive wallpapers Glass UI and visual effects Why I built it Most web demos are landing pages, dashboards, or small single-purpose apps. I wanted to build something that feels more like an environment. I was interested in questions like: Can a web app feel physical and desktop-like? How should windows behave inside a browser viewport? How far can local-first storage go before a backend is actually needed? How do you organize many small apps without making the UI messy? IP Linux became a way to test all of that in one project. The app includes a catalog of built-in apps and tools: Files, Terminal, Browser, Settings, App Store, Music Player, Matrix Rain, games, developer tools, productivity apps, and visual utilities. The virtual file system and user preferences are stored locally in the visitor's browser with IndexedDB/localStorage. There is no backend, no account system, and no required environment variables for the public release. Would love to get feedback on the interaction design, responsiveness, or features!

We've all been there: staring at a clunky, 10-year-old hospital web portal, clicking through endless nested menus just to book a simple check-up or download a PDF lab result. It's tedious, error-prone, and frankly, a waste of human potential. But what if you could just tell an AI, "Book me a dermatologist for next Tuesday and save my blood test results to my health folder," and it just... did it? In this tutorial, we are diving deep into the world of autonomous agents , GPT-4o , and LLM-driven web navigation . By leveraging the revolutionary Browser-use library and Playwright , we’ll build a vision-capable agent that can navigate complex UIs, handle logins, and automate the most frustrating parts of healthcare administration. 🚀 Why Traditional Scraping Fails (and Why Agents Win) Traditional automation tools like Selenium or Puppeteer rely on brittle DOM selectors ( #button-id-342 ). When a hospital updates its website, your script breaks. Using Browser-use with GPT-4o changes the game. Instead of looking for code, the agent sees the page like a human, understanding that a magnifying glass icon means "Search" regardless of the underlying HTML. The Architecture 🏗️ The system logic involves a feedback loop where the LLM perceives the browser state (screenshot + DOM tree), decides on an action, and executes it via Playwright. graph TD A[User Goal: Book Appointment/Download Report] --> B[LangChain Agent / Browser-use] B --> C{Decision Engine: GPT-4o} C --> D[Action: Click/Type/Scroll] D --> E[Playwright Browser Instance] E --> F[Hospital Portal UI] F --> G[Visual & HTML Feedback] G --> C F --> H[Download Lab Report PDF] H --> I[Structured Storage / RAG Pipeline] I --> J[Task Completed ✅] Prerequisites 🛠️ Before we start, ensure you have the following in your tech stack: Python 3.10+ Playwright (The backbone of browser control) Browser-use (The bridge between LLMs and browsers) OpenAI API Key (We'll use GPT-4o for its superior vision capabilities) pip install browser-use

When a Magento store feels slow, merchants usually notice it first on the homepage. When revenue actually slips, we usually find the damage deeper in the funnel. That was the case on a recent mid-market Magento 2 build we inherited. Product pages were acceptable. Search worked. But checkout analytics told a different story. Mobile users were stalling after address entry, re-clicking shipping methods, and abandoning before payment finished rendering. The merchant described it in business terms: "traffic is fine, but checkout feels fragile." They were right. The store was running a fairly typical Magento checkout stack: Luma fallback checkout, several shipping customizations, two payment methods, tax recalculation on step changes, and a handful of third-party scripts that had quietly accumulated over time. Together, they created a familiar Magento problem: too much JavaScript, too many render passes, and too much waiting on the highest-stakes route in the store. Over a 90-day measurement window after launch, checkout completion improved by 34%. Mobile completion improved by 39%. Lab metrics got much better immediately, and field metrics followed. This article covers why we chose React instead of Hyva Checkout, how we implemented the frontend, what moved the numbers, and what we would do differently next time. The problem with Magento's default checkout Magento's default Luma checkout is functional, but performance is rarely its strength. The architecture was designed around Knockout.js components, RequireJS modules, and a lot of UI behavior being layered in over time. Once a real merchant adds shipping estimation, fraud tooling, tax logic, payment widgets, analytics, and address validation, the route becomes busy in all the wrong ways. In this project, our baseline looked like this on a throttled mobile profile: Metric Before (Luma checkout) After (React checkout) Initial checkout route payload 1.8 MB transferred 486 KB transferred LCP 4.2s 1.1s INP 280ms 92ms CLS 0.1

Magento's default Luma checkout loads a heavy Knockout.js stack, dozens of RequireJS modules, and payment iframes that fight for the main thread. For merchants where checkout is the conversion bottleneck, shaving seconds off load and interaction time pays back faster than another homepage hero image. We rebuilt checkout in React— React Checkout Pro —for Magento 2 and Hyvä stores that needed Shopify-like speed without leaving Adobe Commerce. Here is what we measured, what surprised us, and what we would do differently. The problem: checkout is where Core Web Vitals go to die Homepage optimizations are table stakes. Checkout is different: More JavaScript. Payment methods, validators, shipping step observers, and third-party scripts stack on one route. More layout shift. Address suggestions, shipping method lists, and tax updates re-render large DOM regions. More input delay. Autocomplete plugins, reCAPTCHA, and BNPL widgets compete on keydown handlers. On a representative Luma checkout (mid-size US retailer, ~80 SKUs in catalog, 4 payment methods), lab tests before migration showed: Metric Luma checkout (before) React checkout (after) LCP (lab, 4G) 4.8s 2.1s INP (field interaction) 320ms 95ms CLS (full flow) 0.18 0.04 JS transferred (checkout route) ~1.9 MB ~420 KB Time to interactive (est.) 6.2s 2.8s Field data from CrUX lagged lab wins by 4–6 weeks but trended the same direction once cache and CDN rules settled. Your numbers will differ. The pattern we see repeatedly: the biggest win is shipping less JavaScript to checkout , not micro-optimizing the JavaScript you keep. Architecture: React island, Magento brain We did not headless the entire storefront. Magento still owns: Quote totals and tax calculation Shipping rate requests Payment tokenization and order placement APIs Customer session and cart persistence React owns the UI layer: step navigation, form state, validation UX, and optimistic updates while Magento APIs catch up. High-level flow: Browser → React Chec

How treating modals as typed async operations eliminates boolean state, callback chains, and runtime surprises in React apps. React applications often treat modals as UI details. A boolean flag. A conditional render. An onClose callback. That works fine for one dialog. But real products have modals that are actually business flows: confirm this destructive action rename this entity and return the new name pick a date range and apply it resolve a conflict before continuing complete a wizard step before the next one unlocks These flows need more than a boolean. They need typed input, typed output, and a way to await the result — just like any other async operation in your app. const result = await modal . open ( renameReportModal , { reportId : report . id , currentName : report . name , }); if ( result . status === " renamed " ) { await renameReport ({ id : report . id , name : result . name }); } That is the idea behind: npm install @okyrychenko-dev/react-modal-manager zustand A modal lifecycle manager. Not a component. Not a design system. A typed async contract between your app logic and your dialog UI. The problem with traditional modal state In most React apps, modal state starts locally: function ReportsPage () { const [ isRenameOpen , setIsRenameOpen ] = useState ( false ); return ( <> < button onClick = { () => setIsRenameOpen ( true ) } > Rename </ button > { isRenameOpen && ( < RenameModal onClose = { () => setIsRenameOpen ( false ) } /> ) } </> ); } And then real requirements arrive: const [ isRenameOpen , setIsRenameOpen ] = useState ( false ); const [ isDeleteOpen , setIsDeleteOpen ] = useState ( false ); const [ isShareOpen , setIsShareOpen ] = useState ( false ); const [ renameTarget , setRenameTarget ] = useState < Report | null > ( null ); const [ deleteTarget , setDeleteTarget ] = useState < Report | null > ( null ); const [ shareTarget , setShareTarget ] = useState < Report | null > ( null ); The UI is not the problem. The orchestration is: Where d