typescript

A set of TypeScript coding rules for a monorepo, which is one repository containing multiple related packages. It covers strict type checking, safe handling of external data, naming, imports, and public APIs.

In plain words
What is it for?
Use it when editing TypeScript or TSX files, especially shared package APIs, JSON or HTTP data boundaries, serialized scene data, and asset models.
Why use it?
It keeps code consistent across packages and catches unsafe or unclear data handling before it causes errors. It also reduces disagreements about how types and exports should be written.

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/andvolodko/html5-game-editor/typescript
Clone the repo
git clone --depth 1 https://github.com/andvolodko/html5-game-editor

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 725 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 $0.00725
Opus 5 $0.00000 $0.00362
Sonnet 5 $0.00000 $0.00145
Haiku 4.5 $0.00000 $0.00072

Measured 2d ago against content hash 1cbd2e385163, 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 · 34 lines

How it starts

The opening of the file, as written. The whole thing — 34 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TypeScript (repo conventions)

tsconfig.base.json is the source of truth: strict, noUncheckedIndexedAccess, noImplicitOverride, verbatimModuleSyntax.

Typing

  • Do not use any. Prefer unknown at JSON/HTTP/multipart boundaries, then narrow with Zod (parseSceneData, parseAssetDatabase) or explicit guards.
  • Public package exports and constructor/Editor façade methods need explicit types (see @game-editor/editor-core, @game-editor/scene, @game-editor/assets).
  • Prefer interfaces for object shapes (SceneData, AssetRecord, AssetApiClient); prefer type aliases for unions and status literals (ComponentData, DocumentDirtyState, AssetManagerStatus).
  • Serialized variants use discriminated unions on type / kind (e.g. ComponentData, AssetMetadata). Keep discriminants and Zod schemas aligned; enforce invariants like AssetRecord.type === metadata.kind.
  • Avoid type assertions. Allowed only at justified boundaries (e.g. Pixi Assets.loadTexture, JSON.parseunknown then validate). Prefer as const / narrowing over as T.
  • Prefer optional fields (assetId?: string) over | null unless null is meaningful. Use ReadonlySet / readonly T[] for values returned from managers that callers must not mutate.
  • Domain IDs are non-empty strings from createId(prefix) in @game-editor/shared (asset_, node_, comp_, scene_, …). Do not invent parallel ID helpers. Typed errors use DomainError / ValidationError from @game-editor/core — not Result monads.

Imports and packages

  • Relative imports inside packages/apps that emit Node ESM use the .js suffix (./document-manager.js). App/Vite consumers import workspace packages by name (@game-editor/scene), never by deep relative paths into another package’s src.
  • Import types with import type { … } when values are not needed (verbatimModuleSyntax).
  • Export public API through each package’s src/index.ts barrel. Do not reach into another package’s internal files.
  • Respect package dependency direction (.cursor/rules/core.mdc). Do not introduce import cycles; split shared types into @game-editor/scene / @game-editor/assets / @game-editor/shared instead of crossing layers.

Read the full file on GitHub · 34 lines

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 · 34 lines · 0 tokens per session scan A 1cbd2e385163

Subscribe to this mod's changes

typescript is a cursor rule published in the GitHub repository andvolodko/html5-game-editor (5 stars, last pushed 7d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 725 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.