TypeScript .cursorrules for ExpressJs: Jest, Logging, and More

TypeScript ExpressJs Jest Logging .cursorrules prompt file

Avesta Technologies

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TypeScript ExpressJs Jest Logging .cursorrules prompt file

You are a senior TypeScript programmer with experience in the ExpressJs framework and a preference for clean programming and design patterns.

Generate code, corrections, and refactorings that comply with the basic principles and nomenclature.

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.
Use JSDoc to document public classes and methods.
Don't leave blank lines within a function.

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.

Classes

Follow SOLID principles.
Prefer composition over inheritance.
Declare interfaces to define contracts.
Write small classes with a single purpose.
Less than 200 instructions.
Less than 10 public methods.
Less than 10 properties.

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.

Follow this project structure:

src/
├── domain/
│ ├── entities/
│ ├── interfaces/
│ │ ├── dtos/
│ │ └── repos/
│ └── useCases/
├── gateways/
├── infrastructure/
│ ├── repository/
│ │ ├── implementation/
│ │ ├── mappers/
│ │ ├── redis/
│ │ └── sequelize/
│ │ ├── config/
│ │ ├── migrations/
│ │ └── models/
│ └── utils/
└── presentation/
├── middleware/
└── routes/

This structure follows a clean architecture approach with clear separation of concerns:
domain/: Contains core business logic, entities, and use case definitions.
gateways/: Acts as an interface between the domain and external services or APIs.
infrastructure/: Handles external concerns like database access, third-party services, and utility functions.
presentation/: Manages the API routes, middleware, and request/response handling.

Testing

Follow the Arrange-Act-Assert convention for tests.
Write comprehensive unit tests for each function in Use Cases.
Name test variables clearly.
Follow the convention: inputX, mockX, actualX, expectedX, etc.
Write unit tests for each public function in Use Cases.
Use test doubles to simulate dependencies.
- Except for third-party dependencies that are not expensive to execute.
Use the standard Jest framework for testing.
Write end to end tests for each API endpoint.
- Use axios for API requests.
- Use mock data for testing.
- Use the standard Jest framework for testing.

Metrics and logging

Use the winston and morgan libraries for logging.
Use the prom-client library for metrics.
Implement logging and metrics in the API wherever required.

stack:

TypeScript ExpressJs Jest Logging .cursorrules prompt file

Avesta Technologies

About .cursorrules prompt file

What you can build

TypeScript Code Linter Service: Develop a tool that analyzes TypeScript code for adherence to the provided guidelines, suggesting corrections and improvements, and integrates with popular editors like VSCode.
TypeScript Refactoring Tool: Create a web application that allows users to input TypeScript files and outputs refactored code following clean design patterns and guidelines, improving readability and maintainability.
Clean Architecture Code Generator: Build a service that generates starter projects in TypeScript with the specified clean architecture, including directory structure and sample code for entities, interfaces, repositories, and routes.
TypeScript Code Documentation Generator: Develop a tool that automatically generates JSDoc comments for TypeScript methods and classes based on the guidelines, integrating with code editors to assist developers.
TypeScript Testing Assistant: Design an application that guides developers through setting up tests using Jest, following the Arrange-Act-Assert pattern for TypeScript applications, including sample test templates.
Logging and Metrics Dashboard: Offer a solution that integrates with applications to provide a real-time dashboard using winston, morgan, and prom-client for logging and metrics auditing.
TypeScript Training Course: Provide an online course focused on teaching TypeScript best practices, clean architecture, and testing, catering to developers who want to improve code quality and project structure.
ExpressJS Middleware Library: Create a collection of common middleware functions for Express in TypeScript, ready to integrate into projects and following best practices for naming and structure.
API Route Creator: Develop a visual tool that assists developers in defining and generating API routes and middleware structures in TypeScript, aligned with the specified project structure.
Immutability Utilities Library: Introduce a library with utilities to enforce immutability in TypeScript applications, promoting the use of readonly and as const where applicable.

Benefits

Emphasizes the use of TypeScript-specific practices, including strict typing and avoiding 'any', while enforcing comprehensive documentation via JSDoc.
Encourages clean and maintainable code through principles like single-purpose functions, immutability, and appropriate use of design patterns and naming conventions.
Advocates for a well-organized project structure based on clean architecture with distinct folders for domain, infrastructure, gateways, and presentation layers, ensuring separation of concerns.

Synopsis

Developers building scalable applications using TypeScript and ExpressJS will benefit by ensuring clean, maintainable code architecture following SOLID principles integrated with clear documentation and structured testing practices.

Overview of .cursorrules prompt

The .cursorrules file outlines a set of guidelines and principles for writing TypeScript code, specifically using the ExpressJs framework, with a focus on clean programming and adherence to design patterns. It includes detailed rules for code style, nomenclature, functions, data handling, classes, exceptions, and project structure. It also specifies a clean architecture approach, emphasizing the separation of concerns into domain, gateways, infrastructure, and presentation layers. Additionally, it provides guidelines for testing using Jest, metrics and logging practices with winston, morgan, and prom-client libraries, and establishes practices for error handling and code documentation.

TypeScript ExpressJs Jest Logging .cursorrules prompt file

TypeScript ExpressJs Jest Logging .cursorrules prompt file

TypeScript ExpressJs Jest Logging .cursorrules prompt file

About .cursorrules prompt file

What you can build

Benefits

Synopsis

Overview of .cursorrules prompt

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