Cursor
ui
Event Listener Added Multiple Times
After Cursor refactored your component code, event listeners are being attached multiple times. Clicking a button fires the handler multiple times, or scroll events fire excessively.
The useEffect cleanup or listener removal logic was broken.
Error Messages You Might See
Handler called multiple times
Double-firing events
Excessive event firing
Memory leak from listeners
Common Causes
- useEffect missing dependency array, adding listener on every render
- Cleanup function not removing listener
- Multiple components mounting, each adding same global listener
- Event delegation not used, multiple listeners for same event
- Component mounting twice in strict mode (React 18)
How to Fix It
useEffect with cleanup: useEffect(() => { window.addEventListener(...); return () => window.removeEventListener(...); }, []). Empty dependency array ensures once per mount. Use event delegation for many items. In dev, React 18 mounts twice intentionally.
Real developers can help you.
Caio Rodrigues
I'm a full-stack developer focused on building practical and scalable web applications. My main experience is with **React, TypeScript, and modern frontend architectures**, where I prioritize clean code, component reusability, and maintainable project structures.
I have strong experience working with **dynamic forms, state management (Redux / React Hook Form), and complex data-driven interfaces**. I enjoy solving real-world problems by turning ideas into reliable software that companies can actually use in their daily operations.
Beyond coding, I care about **software quality and architecture**, following best practices for componentization, code organization, and performance optimization.
I'm also comfortable working across the stack when needed, integrating APIs, handling business logic, and helping transform prototypes into production-ready systems.
My goal is always to deliver solutions that are **simple, efficient, and genuinely useful for the people using them.**
PawelPloszaj
I'm fronted developer with 10+ years of experience with big projects. I have small backend background too
Jen Jacobsen
I’m a Full-Stack Developer with over 10 years of experience building modern web and mobile applications. I enjoy working across the full product lifecycle — turning ideas into real, well-built products that are intuitive for users and scalable for businesses.
I particularly enjoy building mobile apps, modern web platforms, and solving complex technical problems in a way that keeps systems clean, reliable, and easy to maintain.
Kingsley Omage
Fullstack software engineer passionate about AI Agents, blockchain, LLMs.
Omar Faruk
As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture.
I played a key role in creating a scalable and maintainable platform to support educators and learners globally.
I'm enthusiastic about embracing new challenges and making meaningful contributions.
AUXLE
I am a Full Stack Developer experienced in building Websites, Web apps and Cross Platform Mobile Apps for Startups and Companies.
prajwalfullstack
Hi Im a full stack developer, a vibe coded MVP to Market ready product, I'm here to help
BurnHavoc
Been around fixing other peoples code for 20 years.
Dor Yaloz
SW engineer with 6+ years of experience,
I worked with React/Node/Python
did projects with React+Capacitor.js for ios
Supabase expert
Jared Hasson
Full time lead founding dev at a cyber security saas startup, with 10 yoe and a bachelor's in CS. Building & debugging software products is what I've spent my time on for forever
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
Why is my listener firing twice?
Missing cleanup function in useEffect. Or missing dependency array, adding listener on every render.
What's event delegation?
Add one listener to parent, check event.target. Better than adding listener to every child. Reduces memory.