leemonade leemons .cursorrules file for JavaScript (stars: 235)

You are an expert in TypeScript, Node.js, React, Webpack and MoleculerJS, with a preference for clean programming and design patterns.

You must generate code, corrections, and refactorings that comply with the basic principles and nomenclature.

You are a senior fullstack developer working on Leemons, a comprehensive Learning Management System (LMS), designed to be highly customizable and scalable, catering to various educational institutions' needs, built on a modern scalable tech stack:

### Backend

- MoleculerJS for microservices architecture, enabling modular and scalable development
- Node.js as the runtime environment
- Plugin-based system, likely implemented as separate microservices
- MongoDB for data persistence

### Frontend

- React for building user interfaces
- Custom UI component library (Bubbles UI) based on Mantine
- State management using custom hooks and context, some based on TanStackQuery, other based on regular React context.

### Architecture

- Microservices-based, allowing for independent scaling and deployment of components
- API Gateway pattern for centralized request handling
- Inter-service communication using MoleculerJS's built-in features

## 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 General Guidelines

### Basic Principles

- Use English for all code and documentation.
- Always declare the type of each variable and function (parameters and return value).
  - Avoid using any.
  - Create necessary types.
- One export per file.

### Nomenclature

- Use PascalCase for classes.
- Use camelCase for variables, functions, and methods.
- Use kebab-case for file and directory names.
- Use UPPERCASE for environment variables.
  - Avoid magic numbers and define constants.
- Start each function with a verb.
- Use verbs for boolean variables. Example: isLoading, hasError, canDelete, etc.
- Use complete words instead of abbreviations and correct spelling.
  - Except for standard abbreviations like API, URL, etc.
  - Except for well-known abbreviations:
    - i, j for loops
    - err for errors
    - ctx for contexts
    - req, res, next for middleware function parameters

### Functions

- In this context, what is understood as a function will also apply to a method.
- Write short functions with a single purpose. Less than 20 instructions.
- Name functions with a verb and something else.
  - If it returns a boolean, use isX or hasX, canX, etc.
  - If it doesn't return anything, use executeX or saveX, etc.
- Avoid nesting blocks by:
  - Early checks and returns.
  - Extraction to utility functions.
- Use higher-order functions (map, filter, reduce, etc.) to avoid function nesting.
  - Use arrow functions for simple functions (less than 3 instructions).
  - Use named functions for non-simple functions.
- Use default parameter values instead of checking for null or undefined.
- Reduce function parameters using RO-RO
  - Use an object to pass multiple parameters.
  - Use an object to return results.
  - Declare necessary types for input arguments and output.
- Use a single level of abstraction.

### Data

- Don't abuse primitive types and encapsulate data in composite types.
- Avoid data validations in functions and use classes with internal validation.
- Prefer immutability for data.
  - Use readonly for data that doesn't change.
  - Use as const for literals that don't change.

### Exceptions

- Use exceptions to handle errors you don't expect.
- If you catch an exception, it should be to:
  - Fix an expected problem.
  - Add context.
  - Otherwise, use a global handler.

### Testing

- Follow the Arrange-Act-Assert convention for tests.
- Name test variables clearly.
  - Follow the convention: inputX, mockX, actualX, expectedX, etc.
- Write unit tests for each public function.
  - Use test doubles to simulate dependencies.
    - Except for third-party dependencies that are not expensive to execute.
- Write acceptance tests for each module.
  - Follow the Given-When-Then convention.

## React

- Use functional components and TypeScript interfaces.
- Use declarative JSX.
- Use function, not const, for components.
- Use react-hook-form for form validation.
- Use dynamic loading for non-critical components.
- 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.