Registry / devops / express-response-formatter

express-response-formatter

library2.0.2jsnpmunverified

Express middleware that enhances the response object with a `formatter` property providing readable methods like `ok()`, `created()`, `badRequest()`, etc. Responses are automatically structured: success (2xx/3xx) returns `{ data: ... }`, client/server errors (4xx/5xx) return `{ error: ... }`, and an optional second parameter adds a `meta` field. Version 2.0.2 (latest) ships with TypeScript declarations. It follows a simple, opinionated format and is intended for projects wanting consistent JSON API responses without heavy frameworks. Release cadence is intermittent; maintained as of 2023.

devops

npm install express-response-formatter

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INSTALL

IMPORT

SIG · EXPRESS-RESPONSE-F

express-response-formatter

devopsjavascriptv2.0.2

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.

responseEnhancer

✓ import { responseEnhancer } from 'express-response-formatter';

✗ const responseEnhancer = require('express-response-formatter'); // CommonJS works but TypeScript may require default import

ESM and CJS both supported; named export is primary.

ResponseFormatter

✓ import type { ResponseFormatter } from 'express-response-formatter';

✗ import { ResponseFormatter } from 'express-response-formatter'; // This is a type only, runtime import will fail

TypeScript type import; use when extending or typing request handlers.

FormatterResponse

✓ import type { FormatterResponse } from 'express-response-formatter';

✗ const { FormatterResponse } = require('express-response-formatter'); // Not a runtime value

Type for the response object after enhancement.

Demonstrates attaching the middleware and using the ok() and badRequest() formatter methods with metadata.

import express, { Request, Response } from 'express'; import { responseEnhancer } from 'express-response-formatter'; const app = express(); app.use(responseEnhancer()); app.get('/users', (req: Request, res: Response) => { const users = [{ name: 'Alice' }, { name: 'Bob' }]; const meta = { total: 2, page: 1 }; res.formatter.ok(users, meta); }); app.get('/error', (req: Request, res: Response) => { const errors = [{ detail: 'Invalid input' }]; res.formatter.badRequest(errors); }); app.listen(3000, () => console.log('Server running on port 3000'));

Debug

Known issues

gotcharesponseEnhancer() must be called as a function (invoked) before passing to app.use; forgetting parentheses breaks middleware.

fix

Ensure app.use(responseEnhancer()) not app.use(responseEnhancer).

affects: >=1.0.0

gotchaMethods like ok() and badRequest() do not allow passing an empty array or null; they will still send a 200 response with empty data/error field.

fix

Always pass the data/errors argument, even if empty array.

affects: >=1.0.0

gotchaMetadata object passed as second argument overrides response structure if it contains keys 'data' or 'error'; this can break expected format.

fix

Avoid using 'data' or 'error' keys in meta object; they are reserved.

affects: >=1.0.0

deprecatedThe package does not automatically handle content negotiation; it always sets Content-Type to application/json.

fix

If you need other formats, use a separate middleware before this one.

affects: >=1.0.0

Errors

Common errors & fixes

TypeError: Cannot read properties of undefined (reading 'ok')

responseEnhancer() not applied before route handler, or middleware order incorrect.

fix

Add app.use(responseEnhancer()) before route definitions.

Middleware is not a function

responseEnhancer is not invoked (app.use(responseEnhancer) instead of app.use(responseEnhancer())).

fix

Call responseEnhancer(): app.use(responseEnhancer()).

Property 'formatter' does not exist on type 'Response'

TypeScript type definitions not loaded or incorrect import.

fix

Import types: import { ResponseFormatter } from 'express-response-formatter' and extend Response interface.

data and error are both present in response

Passing meta object with 'data' or 'error' keys that get merged into response.

fix

Ensure meta object does not contain reserved keys 'data' or 'error'.

Upgrade

Version history

2.0.2latest on npm

Audit

Dependencies

expressrequiredpeer dependency; designed to enhance Express response object

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/aofleejay/express-response-formatter ↗

packageexpress-response-formatter ↗

homepagehttps://github.com/aofleejay/express-response-formatter#readme ↗