Registry / auth-security / express-maskdata-middleware

express-maskdata-middleware

library0.1.1jsnpmunverified

Express middleware for masking sensitive data in API responses, built on maskdata. Version 0.1.1 (latest), stable but early stage. Released irregularly. Differentiates by integrating maskdata into Express with simple rule-based configuration for common fields like email, password, phone, SSN, credit card. Supports TypeScript out of the box. Minimal footprint; only dependency is maskdata. Ideal for protecting PII in response bodies without manual transformation.

auth-security web-framework serialization

npm install express-maskdata-middleware

package ↗

INSTALL

IMPORT

SIG · EXPRESS-MASKDATA-M

express-maskdata-middleware

auth-securityjavascriptv0.1.1

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

createMaskingMiddleware

✓ import { createMaskingMiddleware } from 'express-maskdata-middleware'

✗ const { createMaskingMiddleware } = require('express-maskdata-middleware')

Package exports ESM. For CJS use dynamic import or check compatibility; named export only.

MaskingRules

✓ import type { MaskingRules } from 'express-maskdata-middleware'

✗ import { MaskingRules } from 'express-maskdata-middleware'

MaskingRules is exported as a TypeScript type, not a value. Use type import to avoid runtime errors.

default import

✓ import expressMaskDataMiddleware from 'express-maskdata-middleware'

✗ import * as expressMaskDataMiddleware from 'express-maskdata-middleware'

Package has no default export; only named export createMaskingMiddleware is available. This default import will fail at runtime.

Initializes an Express app, creates masking middleware with rules for email and password, and applies to all routes. The /user endpoint returns JSON with sensitive fields automatically masked.

import express from 'express'; import { createMaskingMiddleware } from 'express-maskdata-middleware'; const app = express(); const maskingRules = { emailFields: ['email'], passwordFields: ['password'], phoneFields: ['phoneNumber'], ssnFields: ['ssn'], cardFields: ['creditCard'], }; app.use(createMaskingMiddleware(maskingRules)); app.get('/user', (req, res) => { res.json({ email: 'user@example.com', password: 'supersecretpassword', username: 'testuser', }); }); app.listen(3000, () => console.log('Server running on port 3000'));

Debug

Known issues

gotchaMiddleware only masks JSON responses. Non-JSON responses (e.g., XML, HTML) are not transformed.

fix

Use express.json() and ensure res.json() is used for responses you want masked.

affects: >=0.0.0

gotchaField names in maskingRules must match exact keys in the response object; nested field paths are not supported (e.g., 'user.email' will not match).

fix

Flatten or preprocess nested objects, or use maskdata directly for complex structures.

affects: >=0.0.0

gotchaThe middleware does not mask arrays of objects; only top-level fields and objects at root or immediate children are processed.

fix

Implement custom masking for arrays if needed, or ensure array elements are processed individually.

affects: >=0.0.0

gotchapackage name is misspelled 'express-maskdata-middleware' but actual npm package is 'express-maskdata-middleware' (both correct here; warning for future readers).

fix

Use the exact npm name: `express-maskdata-middleware`.

affects: >=0.0.0

Errors

Common errors & fixes

TypeError: createMaskingMiddleware is not a function

Attempting to use default import or wrong named import (e.g., import * as mask).

fix

Use named import: import { createMaskingMiddleware } from 'express-maskdata-middleware'.

Cannot find module 'express-maskdata-middleware'

Package not installed or misspelled.

fix

Run: npm install express-maskdata-middleware --save

Argument of type '{ emailFields: string[]; }' is not assignable to parameter of type 'MaskingRules'

Missing required properties or TypeScript type mismatch; MaskingRules expects all optional fields but error may arise from strict null checks or version mismatch.

fix

Ensure all used fields are defined in the rules object, or use type assertion: createMaskingMiddleware(rules as MaskingRules).

Upgrade

Version history

0.1.1latest on npm

Audit

Dependencies

maskdatarequiredCore masking engine used by the middleware for all field-level transformations.

expressrequiredPeer dependency required to integrate as middleware in Express applications.

Agent activity

13 hits · last 30 days

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Resources

packagehttps://www.npmjs.com/package/express-maskdata-middleware ↗