Registry / http-networking / string-replace-middleware

string-replace-middleware

library1.1.0jsnpmunverified

Express middleware that performs stream-based string replacement in HTTP response bodies on the fly. Current stable version is 1.1.0, released under MIT license, with infrequent updates. Key differentiator: works on the response stream before sending, unlike typical string replacement that buffers entire responses. Supports configurable Content-Type filtering via regex (default: text/*, application/json, application/xml). Ships TypeScript type declarations. Requires Node >=10 and Express. Not recommended for production with large or streaming responses due to potential performance overhead.

http-networking web-framework

npm install string-replace-middleware

github ↗package ↗

INSTALL

IMPORT

SIG · STRING-REPLACE-MID

string-replace-middleware

http-networkingjavascriptv1.1.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

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

stringReplace

✓ import { stringReplace } from 'string-replace-middleware'

✗ import stringReplace from 'string-replace-middleware'

The library exports a named export, not a default export. ESM import syntax shown; CommonJS require works the same way.

stringReplace

✓ const { stringReplace } = require('string-replace-middleware')

✗ const stringReplace = require('string-replace-middleware')

CommonJS require must use destructuring to obtain the named export. Direct require returns the module object.

stringReplace

✓ const stringReplace = require('string-replace-middleware').stringReplace

✗ const stringReplace = require('string-replace-middleware')

Alternative CommonJS pattern: assign the named export explicitly to a variable.

Sets up an Express app with string replacement middleware that replaces 'foo' with 'bar' and 'hello' with 'world' in all responses matching default content types.

import express from 'express'; import { stringReplace } from 'string-replace-middleware'; const app = express(); app.use(stringReplace({ 'foo': 'bar', 'hello': 'world' })); app.get('/', (req, res) => { res.send('foo says hello'); }); app.listen(3000, () => console.log('Listening on 3000'));

Debug

Known issues

gotchaMiddleware only processes responses with Content-Type matching the regex. Responses without Content-Type or with non-matching types (e.g., image/png) are passed through unmodified.

fix

Verify that your responses set an appropriate Content-Type header. Use the options.contentTypeFilterRegexp to customize matching.

affects: all

gotchaThe middleware buffers the entire response body to perform replacement, which can cause high memory usage and increased latency for large responses or high-traffic endpoints.

fix

Avoid using this middleware for large file downloads or streaming endpoints. Consider alternative approaches like pre-processing strings before sending.

affects: all

gotchaReplacement is applied to the raw response stream, including HTML tags and JavaScript code. Replacements may inadvertently break content syntax (e.g., replacing 'var' in JavaScript).

fix

Use targeted replacements that are unlikely to appear in code or structure. Consider adding logic to avoid replacing inside certain contexts (not provided by the library).

affects: all

Errors

Common errors & fixes

TypeError: stringReplace is not a function

Incorrect import style — using default import instead of named import.

fix

Use `const { stringReplace } = require('string-replace-middleware')` instead of `const stringReplace = require('string-replace-middleware')`.

Cannot find module 'string-replace-middleware'

Package not installed or Node.js version < 10 (engines requirement).

fix

Run `npm install string-replace-middleware` and ensure Node.js >= 10.

TypeError: Cannot read property 'foo' of undefined

If the replacement map contains a key that is a string with special regex characters (e.g., '.'), the library may throw due to improper regex escaping (note: actual library behavior — it uses plain string replace, not regex, so this error unlikely but possible if misuse). Alternatively, this error can occur if the middleware is not applied correctly.

fix

Ensure you call `app.use(stringReplace({...}))` correctly. The library uses string replacement, not regex, so most special characters are safe. Check for proper Express setup.

Upgrade

Version history

1.1.0latest on npm

Audit

Dependencies

expressrequiredPeer dependency; designed as Express middleware and requires the Express request/response object

Agent activity

13 hits · last 30 days

node

Amazon

OpenAI (training)

Resources

githubhttps://github.com/bfncs/string-replace-middleware ↗

packagehttps://www.npmjs.com/package/string-replace-middleware ↗