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Typescript Narrowing

Category: Engineering  ·  Sub-category: languages  ·  Last updated:
lang:typescript
Narrow union types safely with guards, discriminated unions, and exhaustiveness checks. Use when working with values that could be several types, or when the compiler will not let you access a property you know is there.
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From the source SKILL.md

Narrowing is how you go from "this could be several types" to "here it is this one" in a way the compiler trusts. Done well, it makes union types ergonomic and catches the case you forgot; done with casts, it throws away the safety you turned strict mode on for.

What this skill does

Typescript Narrowing is a community-contributed Claude Code skill in the languages sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/typescript-narrowing/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when working with values that could be several types, or when the compiler will not let you access a property you know is there.

Who uses this skill

The Typescript Narrowing Claude Code skill is built for software engineers, backend developers, full-stack teams, and technical leads building and maintaining production systems. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 191,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/typescript-narrowing
curl -L https://claudskills.com/skills/typescript-narrowing/SKILL.md \
  -o ~/.claude/skills/typescript-narrowing/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/typescript-narrowing/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/typescript-narrowing/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\typescript-narrowing\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Telegram

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Typescript Narrowing Claude Code skill?
Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/typescript-narrowing/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.
What does the Typescript Narrowing skill do?
Narrow union types safely with guards, discriminated unions, and exhaustiveness checks. Use when working with values that could be several types, or when the compiler will not let you access a property you know is there.
Is this skill free to install?
Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.
When should I use the Typescript Narrowing skill?
Use Typescript Narrowing when your Claude Code task falls under the Engineering category — specifically in the languages area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Typescript Narrowing" or describe the task and let Claude pick). Browse related skills at /category/engineering/.
What is a Claude Code skill and how does the Typescript Narrowing skill fit in?
A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Typescript Narrowing is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA
Amey-Thakur. (2026). Typescript Narrowing [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/typescript-narrowing/
BibTeX
@misc{typescript-narrowing-2026,
  author    = {Amey-Thakur},
  title     = {Typescript Narrowing [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/typescript-narrowing/}
}

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Grade A · scanned 2026-08-26 — free static scan against the OWASP Agentic Skills Top 10.

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