eslint-plugin-unicode-typography

ESLint plugin to enforce proper Unicode typography characters instead of ASCII approximations. This is similar to smartquotes.js or eslint-plugin-prefer-smart-quotes but includes characters other than just quotes and more granular configuration options.

Why?

Using proper Unicode characters instead of ASCII approximations makes your text more readable and professional:

| Instead of | Use | |------------|-----| | ... | … (ellipsis) | | -- | — (em dash) | | - | – (en dash, see below) | | "quoted" | “quoted” (smart quotes) | | 'quoted' | ‘quoted’ (smart quotes) | | don't | don’t (smart apostrophe) | | 5' 6" | 5′ 6″ (prime symbols) |

Note: The en dash rule specifically looks for a space on either side. Words like well-known and red-tailed should use a hyphen but something like 9am–5pm should use an en dash.

Installation

npm install eslint-plugin-unicode-typography --save-dev
# or
pnpm add -D eslint-plugin-unicode-typography
# or
yarn add -D eslint-plugin-unicode-typography

Usage

Flat Config (ESLint 9+)

// eslint.config.js
import unicodeTypography from 'eslint-plugin-unicode-typography';

export default [
  // Use the recommended config
  unicodeTypography.configs.recommended,

  // Or configure manually
  {
    plugins: {
      'unicode-typography': unicodeTypography,
    },
    rules: {
      'unicode-typography/prefer-unicode': 'warn',
    },
  },
];

Legacy Config (ESLint 7-8)

{
  "plugins": ["unicode-typography"],
  "rules": {
    "unicode-typography/prefer-unicode": "warn"
  }
}

Rule: prefer-unicode

Enforces the use of proper Unicode typography characters.

Default Behavior

By default, the rule checks:

• JSX children (text inside JSX elements) - all elements
• JSX attributes - only title, alt, label, aria-label, aria-describedby

By default, the rule does NOT check:

• String literals - disabled by default
• Template literals - disabled by default

Options

{
  "unicode-typography/prefer-unicode": ["warn", {
    // Replacement toggles (all true by default)
    "ellipsis": true,      // ... → …
    "emdash": true,        // -- → —
    "endash": true,        // " - " → –
    "quotes": true,        // "" '' → "" ''
    "apostrophes": true,   // ' → ' (in contractions)
    "primes": true,        // ' " → ′ ″ (after numbers)

    // Scope options (trinary: true | false | object)
    "checkStringLiterals": false,
    "checkTemplateLiterals": false,
    "checkAttributes": { "onlyAttributes": ["title", "alt", "label", "aria-label", "aria-describedby"] },
    "checkChildren": true
  }]
}

Scope Options

Each scope option accepts three types of values:

checkStringLiterals

Controls checking of string literals in JavaScript/TypeScript.

// Disable (default)
"checkStringLiterals": false

// Enable for all string literals
"checkStringLiterals": true

// Enable only inside specific function calls (e.g., i18n)
"checkStringLiterals": { "onlyFunctions": ["t", "msg", "i18n.t"] }

checkTemplateLiterals

Controls checking of template literals.

// Disable (default)
"checkTemplateLiterals": false

// Enable for all template literals (tagged and untagged)
"checkTemplateLiterals": true

// Enable for specific tagged templates only
"checkTemplateLiterals": { "tags": ["t", "msg"] }

// Enable for untagged templates only
"checkTemplateLiterals": { "untagged": true }

// Enable for both specific tags and untagged
"checkTemplateLiterals": { "tags": ["t"], "untagged": true }

checkAttributes

Controls checking of JSX attribute values.

// Disable
"checkAttributes": false

// Enable for all attributes
"checkAttributes": true

// Enable for specific attributes only (default)
"checkAttributes": { "onlyAttributes": ["title", "alt", "label", "aria-label", "aria-describedby"] }

checkChildren

Controls checking of JSX text content.

// Disable
"checkChildren": false

// Enable for all elements (default)
"checkChildren": true

// Enable for specific elements/components only
"checkChildren": { "onlyComponents": ["p", "span", "Text", "Label"] }

Auto-fix

This rule provides auto-fix support. Run ESLint with --fix to automatically replace ASCII characters with their Unicode equivalents:

eslint --fix src/

Related

License

MIT