Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/chand1012/cursorrules/javascriptgit clone --depth 1 https://github.com/chand1012/cursorrulesWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.00496 |
| Opus 5 | $0.00000 | $0.00248 |
| Sonnet 5 | $0.00000 | $0.00099 |
| Haiku 4.5 | $0.00000 | $0.00050 |
Grade A, and why
javascript scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 77 lines — stays where its author put it; the contents beside it link to each section on GitHub.
JavaScript Best Practices
Modern JavaScript Features
- Use ES modules with
importandexportstatements - Utilize modern features like optional chaining (
?.) and nullish coalescing (??) - Use
constandletovervarfor better scoping - Implement async/await for asynchronous operations
- Use arrow functions for concise syntax and lexical
this - Leverage template literals for string interpolation
- Use destructuring for cleaner object/array handling
Naming Conventions
- Use camelCase for variables and functions
- Use PascalCase for classes
- Use UPPER_CASE for constants
- Use descriptive names with auxiliary verbs (e.g.,
isLoading,hasError) - Use consistent naming across the codebase
Code Organization
- Keep files focused and single-purpose
- Use a consistent directory structure
- Group related functionality together
- Use barrel exports (index.js) for clean imports
- Use absolute imports over relative when appropriate
Functions and Methods
- Keep functions small and focused
- Handle errors appropriately
- Document complex functions
- Use parameter destructuring for cleaner APIs
- Implement proper error boundaries
Best Practices
- Write tests for critical functionality
- Use ESLint and Prettier for code consistency
- Implement proper error handling
- Use proper logging and debugging
- Follow security best practices
- Keep dependencies up to date
Performance
- Implement proper code splitting
- Use lazy loading where appropriate
- Optimize bundle size
- Use proper caching strategies
- Implement proper memoization
- Monitor and optimize render performance
Testing
- Write unit tests for business logic
- Implement integration tests for complex flows
- Use proper testing libraries (Jest, Testing Library)
- Write meaningful test descriptions
- Test error cases and edge conditions
- Maintain good test coverage
Documentation
- Write clear documentation
- Use JSDoc for function documentation
- Document complex algorithms
- Keep README files up to date
- Document configuration options
- Use meaningful commit messages
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 77 lines · 496 tokens per session scan A e80edf25ce56
javascript is a cursor rule published in the GitHub repository chand1012/cursorrules (13 stars, last pushed 9mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 496 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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