lang-typescript

Trigger Keywords

.ts

.tsx

.mts

.cts

<For>

<Show>

<Switch>

<Match>

<Index>

⛔ Forbidden Patterns

1. NO

   any

   : Strictly forbidden. Use

   unknown

   if type is truly not known yet, or define a proper type/interface.
2. NO

   @ts-ignore

   : Do not suppress errors. Fix them. Use

   @ts-expect-error

   ONLY if testing error cases explicitly.
3. NO

   !

   (Non-null Assertion): Avoid

   val!

   . Use optional chaining

   ?.

   or nullish coalescing

   ??

   .
4. NO

   enum

   : Prefer union types (

   type Status = 'active' | 'inactive'

   ) or const objects. Enums add runtime overhead and behave unexpectedly.
5. NO Default Exports: Prefer named exports to ensure consistent naming across the project and better tree-shaking.

🤖 Agent Tool Strategy

1. Discovery: Check for

   justfile

   first. If it exists, use

   just -l

   to list recipes and prefer

   just

   commands over language-specific CLIs (npm, cargo, poetry, etc.). Then, read

   tsconfig.json

   to understand compiler options (strictness, paths, target).
2. Linting: Check

   eslint.config.js

   or

   .eslintrc

   to align with project style.
3. Type Checking: Use

   tsc --noEmit

   to verify type safety after changes if a build script isn't available.
4. Testing: Run tests via

   bun test

   or

   vitest

   to ensure no regressions.
5. File Operations: When creating files, ensure the extension matches the content (

   .tsx

   for JSX,

   .ts

   for logic).

Quick Reference (30 seconds)

.ts

.tsx

.mts

.cts

• TypeScript 5.9: Deferred module evaluation, decorators, satisfies operator
• SolidJS: Fine-grained reactivity, signals, stores
• TanStack Start: Full-stack framework with file-based routing, server functions
• Valibot: Tree-shakable schema validation
• Testing: Vitest, Solid Testing Library, Playwright

Implementation Guide (5 minutes)

• TypeScript 5.9 Key Features (Satisfies, Deferred Modules, Decorators)
• SolidJS Patterns (Signals, Stores, Memos, Resources)
• TanStack Start Patterns (Routes, Server Functions)
• Valibot Schema Patterns
• Advanced State Management

Quick Troubleshooting

bun run typecheck                    # Type check only
bunx tsc --generateTrace ./trace     # Performance trace

bun run dev                         # Development mode
bun run build                       # Check for build errors
rm -rf .vinxi .output && bun run dev  # Clear cache

// Exhaustive check
function assertNever(x: never): never { throw new Error(`Unexpected: ${x}`); }

// Type guard
function isUser(v: unknown): v is User {
  return typeof v === "object" && v !== null && "id" in v;
}

• patterns.md - Implementation patterns (SolidJS, TanStack, Valibot)
• reference.md - Complete API reference, Context7 library mappings, advanced type patterns
• examples.md - Production-ready code examples, full-stack patterns, testing templates

Context7 Integration

// TypeScript - mcp__context7__get_library_docs("/microsoft/TypeScript", "decorators satisfies", 1)
// SolidJS - mcp__context7__get_library_docs("/solidjs/solid", "createSignal createStore", 1)
// TanStack Start - mcp__context7__get_library_docs("/tanstack/start", "server-functions routing", 1)
// TanStack Router - mcp__context7__get_library_docs("/tanstack/router", "file-based-routing loaders", 1)
// Valibot - mcp__context7__get_library_docs("/fabian-hiller/valibot", "schema validation pipe", 1)

Works Well With

• moai-domain-frontend

  - UI components, styling patterns

• moai-domain-backend

  - API design, database integration

• moai-workflow-testing

  - Testing strategies and patterns

• moai-foundation-quality

  - Code quality standards

• moai-essentials-debug

  - Debugging TypeScript applications

Quick Troubleshooting

bun run typecheck                    # Type check only
bunx tsc --generateTrace ./trace     # Performance trace

bun run dev                         # Development mode
bun run build                       # Check for build errors
rm -rf .vinxi .output && bun run dev  # Clear cache

// Exhaustive check
function assertNever(x: never): never { throw new Error(`Unexpected: ${x}`); }

// Type guard
function isUser(v: unknown): v is User {
  return typeof v === "object" && v !== null && "id" in v;
}