🕶️ obscure-string

A tiny utility to mask part of a string — perfect for hiding secrets, emails, API keys, and IDs. Fully customizable and zero dependencies.

✨ Features

• 🔐 Hide sensitive values in logs and UIs
• ⚙️ Customizable mask char, prefix, and suffix lengths
• 🪶 Zero dependencies (<1KB gzipped)
• 🧪 Fully tested with edge case handling
• 🧠 TypeScript definitions included
• 📦 Supports CommonJS, ESM, Node.js, bundlers
• 🖥️ CLI support coming soon

📦 Install

npm install obscure-string
# or
yarn add obscure-string

🚀 Quick Start

const { obscureString } = require('obscure-string');

obscureString('mysecretkey');
// → 'mys*****key'

obscureString('[email protected]', {
  prefixLength: 2,
  suffixLength: 4,
  maskChar: '#',
});
// → 'jo##############.com'

⚙️ Options

| Option | Type | Default | Description | | -------------- | -------- | ------- | ----------------------------------- | | maskChar | string | * | Character used for masking | | prefixLength | number | 3 | Visible characters at the beginning | | suffixLength | number | 3 | Visible characters at the end |

If the input string is shorter than prefixLength + suffixLength, it's returned unchanged.

🧪 Examples

obscureString('mysecretkey');
// → 'mys*****key'

obscureString('supersecretvalue', { prefixLength: 2, suffixLength: 2 });
// → 'su************ue'

obscureString('veryshort', { prefixLength: 5, suffixLength: 5 });
// → 'veryshort' (too short to mask)

obscureString(null);
// → '' (non-string input)

obscureString('1234567890', { prefixLength: 2, suffixLength: 2 });
// → '12******90'

🔠 TypeScript Support

export function obscureString(
  str: string,
  options?: {
    maskChar?: string;
    prefixLength?: number;
    suffixLength?: number;
  }
): string;

🧪 Running Tests

npm test

Uses Jest for unit testing. See __tests__/ for test cases.

🧹 Formatting

npm run format

Uses Prettier with .prettierrc config.

🖥️ CLI (Coming Soon)

A CLI version is planned:

npx obscure-string "my-secret-token" --prefix 2 --suffix 4 --char "#"

👥 Contributing

Contributions welcome!

1. 🍴 Fork the repo
2. 🛠 Create a feature branch
3. ✅ Add tests and update docs
4. 🚀 Open a pull request

✅ Roadmap

• [x] Base string masking
• [x] TypeScript support
• [x] Prettier formatting
• [x] Jest test suite
• [ ] CLI via npx
• [ ] GitHub Actions CI
• [ ] Optional string-type detectors (email, token, etc.)
• [ ] VSCode extension (stretch)

🧾 License

MIT © PDR

🌍 Related Packages

• string-mask – pattern masking (more complex)
• redact-pii – automatic PII redaction
• common-tags – tag helpers for strings

Made with ❤️ to keep your secrets secret.