typescript-docs

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TypeScript Documentation

Generate production-ready TypeScript documentation with layered architecture for multiple audiences. Supports API docs with TypeDoc, ADRs, and framework-specific patterns.

Overview

Use JSDoc annotations for inline documentation, TypeDoc for API reference generation, and ADRs for tracking design choices.

Key capabilities:

TypeDoc configuration and API documentation generation
JSDoc patterns for all TypeScript constructs
ADR creation and maintenance
Framework-specific patterns (NestJS, React, Express, Angular, Vue)
ESLint validation rules for documentation quality
GitHub Actions pipeline setup

When to Use

Use this skill when creating API documentation, architectural decision records, code examples, or framework-specific patterns for NestJS, Express, React, Angular, or Vue.

Quick Reference

Tool	Purpose	Command
TypeDoc	API documentation generation	`npx typedoc`
Compodoc	Angular documentation	`npx compodoc -p tsconfig.json`
ESLint JSDoc	Documentation validation	`eslint --ext .ts src/`

JSDoc Tags

Tag	Use Case
`@param`	Document parameters
`@returns`	Document return values
`@throws`	Document error conditions
`@example`	Provide code examples
`@remarks`	Add implementation notes
`@see`	Cross-reference related items
`@deprecated`	Mark deprecated APIs

Instructions

1. Configure TypeDoc

bash

npm install --save-dev typedoc typedoc-plugin-markdown

json

{
  "entryPoints": ["src/index.ts"],
  "out": "docs/api",
  "theme": "markdown",
  "excludePrivate": true,
  "readme": "README.md"
}

2. Add JSDoc Comments

typescript

/**
 * Service for managing user authentication
 *
 * @remarks
 * Handles JWT-based authentication with bcrypt password hashing.
 *
 * @example
 * ```typescript
 * const authService = new AuthService(config);
 * const token = await authService.login(email, password);
 * ```
 *
 * @security
 * - Passwords hashed with bcrypt (cost factor 12)
 * - JWT tokens signed with RS256
 */
@Injectable()
export class AuthService {
  /**
   * Authenticates a user and returns access tokens
   * @param credentials - User login credentials
   * @returns Authentication result with tokens
   * @throws {InvalidCredentialsError} If credentials are invalid
   */
  async login(credentials: LoginCredentials): Promise<AuthResult> {
    // Implementation
  }
}

3. Create an ADR

markdown

# ADR-001: TypeScript Strict Mode Configuration

## Status
Accepted

## Context
What is the issue motivating this decision?

## Decision
What change are we proposing?

## Consequences
What becomes easier or more difficult?

4. Set Up CI/CD Pipeline

yaml

name: Documentation
on:
  push:
    branches: [main]
    paths: ['src/**', 'docs/**']

jobs:
  generate-docs:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'npm'
      - run: npm ci
      - run: npm run docs:generate
      - run: npm run docs:validate

5. Validate Documentation

json

{
  "rules": {
    "jsdoc/require-description": "error",
    "jsdoc/require-param-description": "error",
    "jsdoc/require-returns-description": "error",
    "jsdoc/require-example": "warn"
  }
}

If validation fails: review ESLint errors, fix JSDoc comments (add missing descriptions, add @param/@returns/@throws where absent), re-run eslint --ext .ts src/ until all errors pass before committing.

Examples

Documenting a React Hook

typescript

/**
 * Custom hook for fetching paginated data
 *
 * @remarks
 * This hook manages loading states, error handling, and automatic
 * refetching when the page or filter changes.
 *
 * @example
 * ```tsx
 * function UserList() {
 *   const { data, isLoading, error } = usePaginatedData('/api/users', {
 *     page: currentPage,
 *     limit: 10
 *   });
 *
 *   if (isLoading) return <Spinner />;
 *   if (error) return <ErrorMessage error={error} />;
 *   return <UserTable users={data.items} />;
 * }
 * ```
 *
 * @param endpoint - API endpoint to fetch from
 * @param options - Pagination and filter options
 * @returns Paginated response with items and metadata
 */
export function usePaginatedData<T>(
  endpoint: string,
  options: PaginationOptions
): UsePaginatedDataResult<T> {
  // Implementation
}

Documenting a Utility Function

typescript

/**
 * Validates email addresses using RFC 5322 specification
 *
 * @param email - Email address to validate
 * @returns True if email format is valid
 *
 * @example
 * ```typescript
 * isValidEmail('user@example.com'); // true
 * isValidEmail('invalid-email');      // false
 * ```
 *
 * @performance
 * O(n) where n is the email string length
 *
 * @see {@link https://tools.ietf.org/html/rfc5322} RFC 5322 Specification
 */
export function isValidEmail(email: string): boolean {
  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  return emailRegex.test(email);
}

NestJS Controller Documentation

typescript

/**
 * REST API endpoints for user management
 *
 * @remarks
 * All endpoints require authentication via Bearer token.
 * Rate limiting: 100 requests per minute per user.
 *
 * @example
 * ```bash
 * curl -H "Authorization: Bearer <token>" https://api.example.com/users/123
 * ```
 *
 * @security
 * - All endpoints use HTTPS
 * - JWT tokens expire after 1 hour
 * - Sensitive data is redacted from logs
 */
@Controller('users')
export class UsersController {
  /**
   * Retrieves a user by ID
   * @param id - User UUID
   * @returns User profile (password excluded)
   */
  @Get(':id')
  async getUser(@Param('id') id: string): Promise<UserProfile> {
    // Implementation
  }
}

Best Practices

Document Public APIs: All public methods, classes, and interfaces
Use `@example`: Provide runnable examples for complex functions
Include `@throws`: Document all possible errors
Add `@see`: Cross-reference related functions/types
Use `@remarks`: Add implementation details and notes
Document Generics: Explain generic constraints and usage
Include Performance Notes: Document time/space complexity
Add Security Warnings: Highlight security considerations
Keep Updated: Update docs when code changes
Don't document obvious code: Focus on why, not what

Constraints and Warnings

Private Members: Use @private or exclude from TypeDoc output
Complex Types: Document generic constraints and type parameters
Breaking Changes: Use @deprecated with migration guidance
Security Info: Never include secrets or credentials in documentation
Link Validity: Ensure @see references point to valid locations
Example Code: All examples should be runnable and tested
Versioning: Keep documentation in sync with code versions

References

[references/jsdoc-patterns.md](references/jsdoc-patterns.md) — JSDoc patterns for interfaces, functions, classes, generics, and unions
[references/framework-patterns.md](references/framework-patterns.md) — Framework-specific patterns for NestJS, React, Express, and Angular
[references/adr-patterns.md](references/adr-patterns.md) — ADR templates and examples
[references/pipeline-setup.md](references/pipeline-setup.md) — CI/CD pipeline configuration for documentation
[references/validation.md](references/validation.md) — ESLint rules and validation checklists
[references/typedoc-configuration.md](references/typedoc-configuration.md) — Complete TypeDoc configuration options
[references/examples.md](references/examples.md) — Additional code examples

TypeScript Documentation

Overview

When to Use

Quick Reference

JSDoc Tags

Instructions

1. Configure TypeDoc

2. Add JSDoc Comments

3. Create an ADR

4. Set Up CI/CD Pipeline

5. Validate Documentation

Examples

Documenting a React Hook

Documenting a Utility Function

NestJS Controller Documentation

Best Practices

Constraints and Warnings

References

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