# TypeScript Best Practices

> Idiomatic TypeScript patterns for clean, maintainable code.

- Skill: `fierzone/typescript-best-practices` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add fierzone/typescript-best-practices`
- Raw SKILL.md: https://api.skillmd.com/api/skills/fierzone/typescript-best-practices/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools, AI & ML
- Author: fierzone (https://skillmd.com/u/fierzone)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/fierzone/typescript-best-practices

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# TypeScript Best Practices

## **Priority: P1 (OPERATIONAL)**

## Implementation Guidelines

- **Naming**: Classes/Types=`PascalCase`, vars/funcs=`camelCase`, consts=`UPPER_SNAKE`. Prefix `I` only if needed.
- **Functions**: Arrows for callbacks; regular for exports. Always type public API returns.
- **Modules**: Named exports only. Import order: external → internal → relative.
- **Async**: Use `async/await`, not raw Promises. `Promise.all()` for parallel.
- **Classes**: Explicit access modifiers. Favor composition. Use `readonly`.
- **Types**: Use `never` for exhaustiveness, `asserts` for runtime checks.
- **Optional**: Use `?:`, not `| undefined`.
- **Imports**: Use `import type` for tree-shaking.

## Anti-Patterns

- **No Default Exports**: Use named exports.
- **No Implicit Returns**: Specify return types.
- **No Unused Variables**: Enable `noUnusedLocals`.
- **No `require`**: Use ES6 `import`.
- **No Empty Interfaces**: Use `type` or non-empty interface.
- **Use any**: Never use `any`, use `unknown` only when necessary.

## Reference & Examples

See [references/examples.md](references/examples.md) for code samples including:

- Immutable Interfaces
- Exhaustiveness Checking
- Assertion Functions
- Dependency Injection Patterns
- Import Organization

## Related Topics

language | tooling | security