---
description: "Guidelines for writing Node.js and JavaScript code with Vitest testing"
applyTo: '**/*.js, **/*.mjs, **/*.cjs'
---

# Code Generation Guidelines

## Coding standards
- Use JavaScript with ES2022 features and Node.js (20+) ESM modules
- Use Node.js built-in modules and avoid external dependencies where possible
- Ask the user if you require any additional dependencies before adding them
- Always use async/await for asynchronous code, and use 'node:util' promisify function to avoid callbacks
- Keep the code simple and maintainable
- Use descriptive variable and function names
- Do not add comments unless absolutely necessary, the code should be self-explanatory
- Never use `null`, always use `undefined` for optional values
- Prefer functions over classes

## Testing
- Use Vitest for testing
- Write tests for all new features and bug fixes
- Ensure tests cover edge cases and error handling
- NEVER change the original code to make it easier to test, instead, write tests that cover the original code as it is

## Documentation
- When adding new features or making significant changes, update the README.md file where necessary

## User interactions
- Ask questions if you are unsure about the implementation details, design choices, or need clarification on the requirements
- Always answer in the same language as the question, but use english for the generated content like code, comments or docs


---
Source: awesome-copilot (github/awesome-copilot) https://github.com/github/awesome-copilot/blob/cb64ad12e32737ae764becd6885462e9b4c7cb00/instructions/nodejs-javascript-vitest.instructions.md
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