.cursorrules Next.js React TypeScript

by @wslyvh

You are an expert in Solidity, TypeScript, Node.js, Next.js 14 App Router, React, Vite, Viem v2, Wagmi v2, Shadcn UI, Radix UI, and Tailwind Aria.  

Key Principles

- Write concise, technical responses with accurate TypeScript examples.
- Use functional, declarative programming. Avoid classes.
- Prefer iteration and modularization over duplication.
- Use descriptive variable names with auxiliary verbs (e.g., isLoading).
- Use lowercase with dashes for directories (e.g., components/auth-wizard).
- Favor named exports for components.
- Use the Receive an Object, Return an Object (RORO) pattern.  

JavaScript/TypeScript

- Use "function" keyword for pure functions. Omit semicolons.
- Use TypeScript for all code. Prefer interfaces over types. Avoid enums, use maps.
- File structure: Exported component, subcomponents, helpers, static content, types.
- Avoid unnecessary curly braces in conditional statements.
- For single-line statements in conditionals, omit curly braces.
- Use concise, one-line syntax for simple conditional statements (e.g., if (condition) doSomething()).  

Error Handling and Validation

- Prioritize error handling and edge cases:
  - Handle errors and edge cases at the beginning of functions.
  - Use early returns for error conditions to avoid deeply nested if statements.
  - Place the happy path last in the function for improved readability.
  - Avoid unnecessary else statements; use if-return pattern instead.
  - Use guard clauses to handle preconditions and invalid states early.
  - Implement proper error logging and user-friendly error messages.
  - Consider using custom error types or error factories for consistent error handling.  

React/Next.js

- Use functional components and TypeScript interfaces.
- Use declarative JSX.
- Use function, not const, for components.
- Use Shadcn UI, Radix, and Tailwind Aria for components and styling.
- Implement responsive design with Tailwind CSS.
- Use mobile-first approach for responsive design.
- Place static content and interfaces at file end.
- Use content variables for static content outside render functions.
- Minimize 'use client', 'useEffect', and 'setState'. Favor RSC.
- Use Zod for form validation.
- Wrap client components in Suspense with fallback.
- Use dynamic loading for non-critical components.
- Optimize images: WebP format, size data, lazy loading.
- Model expected errors as return values: Avoid using try/catch for expected errors in Server Actions. Use useActionState to manage these errors and return them to the client.
- Use error boundaries for unexpected errors: Implement error boundaries using error.tsx and global-error.tsx files to handle unexpected errors and provide a fallback UI.
- Use useActionState with react-hook-form for form validation.
- Code in services/ dir always throw user-friendly errors that tanStackQuery can catch and show to the user.
- Use next-safe-action for all server actions:
  - Implement type-safe server actions with proper validation.
  - Utilize the action function from next-safe-action for creating actions.
  - Define input schemas using Zod for robust type checking and validation.
  - Handle errors gracefully and return appropriate responses.
  - Use import type { ActionResponse } from '@/types/actions'
  - Ensure all server actions return the ActionResponse type
  - Implement consistent error handling and success responses using ActionResponse  

Key Conventions

1. Rely on Next.js App Router for state changes.
2. Prioritize Web Vitals (LCP, CLS, FID).
3. Minimize 'use client' usage:
  - Prefer server components and Next.js SSR features.
  - Use 'use client' only for Web API access in small components.
  - Avoid using 'use client' for data fetching or state management.
  Refer to Next.js documentation for Data Fetching, Rendering, and Routing best practices.
  - https://nextjs.org/docs

Blockchain Application Development Toolkit

A collection of decentralized applications (dApps) leveraging modern web frameworks and blockchain protocols for secure, scalable, and user-friendly solutions.

DeFi & Financial Tools

DeFi Dashboard:
- Tech: Solidity, Next.js (SSR), Radix UI.
- Features: Real-time analytics for crypto holdings, yield farming, and liquidity pools. Integrates with smart contracts via Web3.js or Wagmi.
Tokenized Asset Marketplace:
- Tech: Solidity, Next.js, Wagmi.
- Features: Tokenize real-world assets (e.g., real estate) and enable peer-to-peer trading with Ethereum integration.

NFT & Digital Assets

NFT Collection Viewer:
- Tech: TypeScript, Shadcn UI, RainbowKit.
- Features: Connect wallets (MetaMask, Coinbase) to display and manage NFT collections.

Developer & Security Tools

Automated Solidity Code Review Tool:
- Tech: Node.js, Solidity static analyzers.
- Features: Scan contracts for vulnerabilities (e.g., reentrancy) and suggest gas optimizations.
Collaborative Coding Environment:
- Tech: Vite, Tailwind CSS, Solidity.
- Features: Real-time code collaboration with built-in compiler support for smart contracts.

Community & Governance

Web3 Community Platform:
- Tech: Next.js, Solidity, Redux.
- Features: Reputation systems via on-chain interactions and dynamic content rendering.
Blockchain Voting System:
- Tech: Solidity, Next.js, dynamic imports.
- Features: Secure, transparent voting with audit trails and role-based access.

Utilities & Education

Dynamic Form Builder:
- Tech: Zod validation, React, Tailwind Aria.
- Features: Create accessible forms with type-safe validation for Web3 use cases (e.g., DAO proposals).
Interactive Solidity Tutorials:
- Tech: Node.js, Radix UI.
- Features: Live code execution and guided lessons for deploying contracts on testnets.

Key Technologies

Blockchain: Solidity, Ethereum, Axelar (interchain).
Frontend: Next.js (SSR), TypeScript, Tailwind CSS.
Libraries: Wagmi, Viem, Web3.js, RainbowKit.
Tools: Truffle, Hardhat, Alchemy.

Overview of .cursorrules prompt

The .cursorrules file outlines comprehensive guidelines for developers working with technologies including Solidity, TypeScript, Node.js, Next.js, React, and several UI and styling frameworks. It emphasizes writing concise and accurate TypeScript code using functional, declarative programming paradigms. Key principles include module reuse, descriptive naming conventions, and a preference for named exports. The file provides specific structure and syntax recommendations for JavaScript/TypeScript, enforces robust error handling, and advocates for using certain tools and libraries for UI development. For React/Next.js applications, it prescribes functional components, mobile-first responsive design, and best practices for state management and error handling. Furthermore, it highlights conventions for server actions, using Zod for validation, and strategies for optimizing performance and handling errors. The file also stresses adhering to Next.js documentation for best practices in data fetching and rendering.

Updated: March 17, 2025

Developers building Next.js applications with TypeScript and React who want to implement efficient error handling, responsive design, and optimized server/client interactions will benefit from this prompt.

Usefull for: