typescript

A set of coding standards for TypeScript, a programming language that adds type information to JavaScript. It covers type safety, modules, scripts, decorators, error handling, and code style.

In plain words
What is it for?
Use it when writing or reviewing TypeScript application code and scripts, especially code using asynchronous operations, reusable types, or strict linting.
Why use it?
It gives contributors consistent ways to structure TypeScript code and catches patterns that can make code harder to understand or maintain.

Cursor rule for Cursor

Install

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.

agentmods
npx agentmods add rules/m3au/playwright-bdd-cursor-template/typescript
Clone the repo
git clone --depth 1 https://github.com/m3au/playwright-bdd-cursor-template

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 362 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What 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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00362
Opus 5 $0.00000 $0.00181
Sonnet 5 $0.00000 $0.00072
Haiku 4.5 $0.00000 $0.00036

Measured 2d ago against content hash 6e34598361aa, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

typescript 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 2d ago.

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.

.cursor/rules/typescript.mdc · 49 lines

What it actually says

TypeScript Standards

Type Safety

  • N: use any or unknown without type guards
  • A: use generics for reusable code
  • A: define interfaces for object shapes
  • A: use explicit return types for functions
  • See tsconfig.json for strict mode configuration

Import/Export Patterns

  • A: use ES modules (import/export) only
  • A: use type imports: import type for type-only imports
  • See existing files for import patterns

Decorator Support

  • See tests/e2e/poms/**/*.ts for decorator usage examples

Script Files

  • A: use TypeScript (.ts) for all script files in scripts/ directory
  • N: use .mjs, .js, or other JavaScript formats for scripts
  • Use bun scripts/<name>.ts to execute scripts directly
  • See existing scripts in scripts/ for examples

Best Practices

  • A: use strict mode and proper async/await typing
  • A: use discriminated unions for type narrowing
  • A: handle errors with proper types
  • A: prefer const assertions over type assertions when possible
  • See eslint.config.mjs for TypeScript ESLint rules

Code Style

Conditional Statements

  • A: use one-liners for simple if statements with single statement
  • A: prefer ternary operators over if-else with early returns when both branches execute
  • A: use early returns for error handling and validation checks
  • A: keep ternary operators readable - N: deeply nested ternaries
Changes

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.

  1. 2d ago First seen · 49 lines · 0 tokens per session scan A 6e34598361aa

Subscribe to this mod's changes

typescript is a cursor rule published in the GitHub repository m3au/playwright-bdd-cursor-template (2 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 362 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 2026-08-31.