---
name: hygiene
description: Use when making code changes to ensure they pass VS Code's hygiene checks. Covers the pre-commit hook, unicode restrictions, string quoting rules, copyright headers, indentation, formatting, ESLint, and stylelint. Run the hygiene check before declaring work complete.
---

# Hygiene Checks

VS Code runs a hygiene check as a git pre-commit hook. Commits will be rejected if hygiene fails.

## Running the hygiene check

**Always run the pre-commit hygiene check before declaring work complete.** This catches issues that would block a commit.

To run the hygiene check on your staged files:

```bash
npm run precommit
```

This executes `node --experimental-strip-types build/hygiene.ts`, which scans only **staged files** (from `git diff --cached`).

To check specific files directly (without staging them first):

```bash
node --experimental-strip-types build/hygiene.ts path/to/file.ts
```

## What it checks

The hygiene linter scans staged files for issues including (but not limited to):

- **Unicode characters**: Non-ASCII characters (em-dashes, curly quotes, emoji, etc.) are rejected. Use ASCII equivalents in comments and code. Suppress with `// allow-any-unicode-next-line` or `// allow-any-unicode-comment-file`.
- **Double-quoted strings**: Only use `"double quotes"` for externalized (localized) strings. Use `'single quotes'` everywhere else.
- **Copyright headers**: All files must include the Microsoft copyright header.
- **Indentation**: Tabs only, no spaces for indentation.
- **Formatting**: TypeScript files must match the formatter output (run `Format Document` to fix).
- **ESLint**: TypeScript files are linted with ESLint.
- **Stylelint**: CSS files are linted with stylelint.