@philiprehberger/mask-kit

v0.2.1

Published

3 months ago

Data masking and redaction for logs and APIs

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@philiprehberger/mask-kit

Data masking and redaction for logs and APIs

Installation

npm install @philiprehberger/mask-kit

Usage

import { maskEmail, maskCreditCard, maskObject } from '@philiprehberger/mask-kit';

maskEmail('[email protected]');     // "u***@e******.com"
maskCreditCard('4111111111111111'); // "************1111"

const safe = maskObject(requestBody, {
  rules: ['password', 'secret', /token/i, 'creditCard'],
});
logger.info('Request', safe);

Format-Preserving Masks

Keep delimiters and separators in place while masking alphanumeric characters:

import { maskFormatPreserving } from '@philiprehberger/mask-kit';

maskFormatPreserving('(555) 123-4567');
// "(***) ***-****"

maskFormatPreserving('(555) 123-4567', { revealLast: 4 });
// "(***) ***-4567"

maskFormatPreserving('4111-2222-3333-4444', { revealLast: 4, revealFirst: 4 });
// "4111-****-****-4444"

Configurable Reveal Count

Control exactly how many characters remain visible:

import { revealFirst, revealLast } from '@philiprehberger/mask-kit';

revealFirst('secretdata', 3);   // "sec*******"
revealLast('secretdata', 4);    // "******data"
revealFirst('abc', 5);          // "abc" (no masking if count >= length)
revealLast('token_xyz', 3, { char: '#' }); // "######xyz"

Regex-Based Masking

Mask substrings that match a regular expression:

import { maskByPattern } from '@philiprehberger/mask-kit';

// Mask all digits
maskByPattern('Order #12345 shipped', /\d+/);
// "Order #***** shipped"

// Mask email-like patterns in free text
maskByPattern('Contact [email protected] for info', /[^\s@]+@[^\s@]+/);
// "Contact ************* for info"

// Mask SSN patterns
maskByPattern('SSN: 123-45-6789', /\d{3}-\d{2}-\d{4}/);
// "SSN: ***********"

Deep Object Masking

Recursively traverse nested objects and arrays, masking values by key name:

import { maskDeep } from '@philiprehberger/mask-kit';

const input = {
  user: {
    name: 'Alice',
    password: 'hunter2',
    addresses: [
      { street: '123 Main St', ssn: '999-00-1234' },
    ],
  },
  apiKey: 'sk-abc123',
};

maskDeep(input, ['password', 'ssn', 'apiKey']);
// {
//   user: {
//     name: 'Alice',
//     password: '*******',
//     addresses: [
//       { street: '123 Main St', ssn: '***********' },
//     ],
//   },
//   apiKey: '********',
// }

API

| Function | Description | |----------|-------------| | maskEmail(email) | Mask email preserving structure | | maskCreditCard(card) | Show last 4 digits | | maskPhone(phone) | Show last 3 digits | | maskToken(token) | Show first/last 4 chars | | maskIP(ip) | Mask middle octets | | maskCustom(str, options?) | Custom masking with position control | | maskFormatPreserving(value, options?) | Mask alphanumeric chars while keeping delimiters | | revealFirst(value, count, options?) | Reveal first N characters, mask the rest | | revealLast(value, count, options?) | Reveal last N characters, mask the rest | | maskByPattern(value, regex, options?) | Mask substrings matching a regex pattern | | maskObject(obj, { rules }) | Deep-walk and mask matching keys with auto-detection | | maskDeep(obj, sensitiveKeys, options?) | Recursively mask values by key name | | detectType(value) | Auto-detect value type |