type-narrowing
Use when working with union types. Use when handling nullable values. Use when TypeScript says a value might be undefined. Use when working with discriminated unions.
SKILL.md
Type narrowing is the process by which TypeScript refines a type from broad to more specific based on control flow.
Master narrowing to write cleaner code without type assertions, and to help TypeScript understand your logic.
If you're using as Type inside an if block, you can probably narrow instead.
Use when working with union types. Use when handling nullable values. Use when TypeScript says a value might be undefined. Use when working with discriminated unions. Source: marius-townhouse/effective-typescript-skills.
Facts (cite-ready)
Stable fields and commands for AI/search citations.
- Install command
npx skills add https://github.com/marius-townhouse/effective-typescript-skills --skill type-narrowing- Category
- </>Dev Tools
- Verified
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- First Seen
- 2026-02-05
- Updated
- 2026-02-18
Quick answers
What is type-narrowing?
Use when working with union types. Use when handling nullable values. Use when TypeScript says a value might be undefined. Use when working with discriminated unions. Source: marius-townhouse/effective-typescript-skills.
How do I install type-narrowing?
Open your terminal or command line tool (Terminal, iTerm, Windows Terminal, etc.) Copy and run this command: npx skills add https://github.com/marius-townhouse/effective-typescript-skills --skill type-narrowing Once installed, the skill will be automatically configured in your AI coding environment and ready to use in Claude Code or Cursor
Where is the source repository?
https://github.com/marius-townhouse/effective-typescript-skills
Details
- Category
- </>Dev Tools
- Source
- user
- First Seen
- 2026-02-05