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dat-middleware

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library1.10.4jsnpmunverified

dat-middleware is an Express.js middleware library that provides a fluent and declarative API for common request data operations. It focuses on validating and transforming `req.body`, `req.query`, and `req.params` against various criteria such as required fields, data types (string, number, array, boolean, object, function), specific class instances (`instanceOf`), and regular expressions (`matches`). Developers can also integrate custom validation logic using the `validate()` method. Upon validation failure, the middleware automatically calls `next()` with a 400 Bad Request error object generated by `spumko/boom`, simplifying error handling. The current stable version is 1.10.4. Given its last update several years ago, it operates primarily in a maintenance mode, offering a stable but not actively developed solution for Express input validation. Its key differentiator is the chaining syntax for defining validation rules directly within the middleware stack.

web-frameworkhttp-networkingauth-securitytestingserialization
npm install dat-middleware
github ↗package ↗
INSTALL
IMPORT
SIG · DAT-MIDDLEWARE
D
dat-middleware
web-frameworkjavascriptv1.10.4
Install
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Import
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Disk
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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.

mw
✓ const mw = require('dat-middleware');
✗ import mw from 'dat-middleware';
dat-middleware is a CommonJS module and does not natively support ES module imports. Direct ESM usage will require a CommonJS wrapper or bundler configuration.
Boom
✓ const Boom = require('dat-middleware').Boom;
✗ import { Boom } from 'dat-middleware';
The Boom error object generator is exposed as a property of the main 'mw' export. The underlying 'spumko/boom' library it uses is deprecated.
mw.body() / mw.query() / mw.params()
✓ app.use(mw.body('key').require());
✗ app.use(body('key').require());
The validation chain methods (e.g., `body`, `query`, `params`) are accessed as properties of the main `mw` export.

This quickstart sets up an Express server with `dat-middleware` to validate request body parameters for a `/user` endpoint, demonstrating required fields, type checks, regex matching, and custom validation.

var mw = require('dat-middleware'); var express = require('express'); var app = express(); var bodyParser = require('body-parser'); // Needed for req.body app.use(bodyParser.json()); // To parse JSON bodies // Custom validation function example: ensures a string is exactly 24 characters function is24Chars (val) { if (typeof val !== 'string') { return mw.Boom.badRequest('must be a string'); } return (val.length !== 24) ? mw.Boom.badRequest('is not 24 characters'): null; // pass } // Define a route that uses dat-middleware for validation and transformation app.post('/user', // Require 'name' and 'age' in the request body mw.body('name', 'age').require(), // Ensure 'age' is a number mw.body('age').number(), // Ensure 'id' matches a specific regular expression (e.g., MongoDB ObjectID format) mw.body('id').matches(/^[a-fA-F0-9]{24}$/), // Apply custom validation to 'description' mw.body('description').validate(is24Chars), // If all validations pass, process the request function (req, res) { res.json({ message: 'User data validated and processed!', data: req.body }); } ); // Start the server const PORT = process.env.PORT || 3000; app.listen(PORT, () => { console.log(`Server listening on port ${PORT}`); console.log('Test with valid data:'); console.log(` curl -X POST -H "Content-Type: application/json" -d '{"name":"John Doe","age":30,"id":"60c72b2f9c1d44001c8c4e4e", "description": "This is a 24 char string"}' http://localhost:${PORT}/user`); console.log('Test with invalid age (not a number):'); console.log(` curl -X POST -H "Content-Type: application/json" -d '{"name":"Jane Doe","age":"thirty","id":"60c72b2f9c1d44001c8c4e4e", "description": "This is a 24 char string"}' http://localhost:${PORT}/user`); console.log('Test with missing name:'); console.log(` curl -X POST -H "Content-Type: application/json" -d '{"age":30,"id":"60c72b2f9c1d44001c8c4e4e", "description": "This is a 24 char string"}' http://localhost:${PORT}/user`); });
Debug
Known issues
gotchadat-middleware is a CommonJS module and requires explicit configuration (e.g., bundler support or a wrapper) to be used directly in an ES Module-only Node.js environment or browser builds.
fix
For Node.js ESM projects, consider using a CommonJS wrapper or a different, modern validation library. For browser builds, ensure your bundler (webpack, rollup) is configured to handle CommonJS modules.
affects: >=1.0.0
deprecatedThe library internally uses 'spumko/boom' (now '@hapi/boom'), an older version of the Boom error handling library. While functional, it might not be compatible with newer versions of Boom or related Hapi ecosystem tools.
fix
Be aware that custom error handling or integration with other Hapi libraries might require adapting to the older Boom version. Consider migrating to a more actively maintained validation library for new projects.
affects: >=1.0.0
gotchaError handling relies on Express's standard next(err) mechanism. The errors are Boom objects (HTTP 400). If you have custom error middleware, ensure it can properly interpret and respond to these error types.
fix
Implement an Express error handling middleware function (e.g., `app.use(function (err, req, res, next) { ... })`) that specifically checks for Boom errors (e.g., `err.isBoom`) to extract status codes and messages correctly.
affects: >=1.0.0
gotchaThe `instanceOf` validation method relies on JavaScript's prototype chain. This might not behave as expected when dealing with objects passed across different realms (e.g., if objects are deserialized from JSON or come from different Node.js contexts), or if the `Class` constructor is not the exact one used to create the instance.
fix
For complex object validation, prefer `validate()` with a custom function that performs structural checks, or use a dedicated schema validation library that offers more robust type and structure validation.
affects: >=1.0.0
Errors
Common errors & fixes
body parameter "key1" is required
A parameter specified by `.require()` was missing from `req.body`, `req.query`, or `req.params`.
fix
Ensure the client sends all parameters specified by `.require()` in the request body (e.g., JSON), query string, or URL parameters.
body parameter "key1" must be an array
A parameter that was expected to be an array type did not receive an array.
fix
Verify that the client sends the specified parameter as a valid JSON array or an array in query string/URL parameters (e.g., `?key1[]=val1&key1[]=val2`).
body parameter "key1" is not 24 characters
A custom validation function provided to `.validate()` returned a Boom error because the input value did not meet its specified criteria.
fix
Adjust the client input to satisfy the custom validation logic defined by the `.validate()` middleware for that parameter.
body parameter "key1" must match /^hello/
A string parameter did not conform to the regular expression pattern defined in the `.matches()` middleware.
fix
Ensure the string value for the parameter precisely matches the regular expression pattern specified in the `.matches()` middleware.
Upgrade
Version history
1.10.4latest on npm
Audit
Dependencies
expressrequiredRuntime dependency for integrating middleware into an Express application.
boomrequiredUsed internally for generating standardized HTTP error objects (400 Bad Request) on validation failure. Note: refers to the 'spumko/boom' package, which is an older version of the library now maintained as '@hapi/boom'.
Agent activity
17 hits · last 30 days
node
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Resources
githubhttps://github.com/tjmehta/dat-middleware ↗
packagehttps://www.npmjs.com/package/dat-middleware ↗
dat-middleware — npm install dat-middleware · libregistry