Registry / http-networking / content-type

content-type

JSON →
library1.0.5jsnpmunverified

The `content-type` package provides a robust utility for creating and parsing HTTP Content-Type headers in Node.js applications, adhering strictly to RFC 7231. It is currently at version 1.0.5, indicating a mature and stable library. The release cadence is infrequent, primarily focusing on performance improvements and minor fixes, suggesting a low-churn, well-maintained codebase. Its core functionality involves parsing a Content-Type string (or directly from `req`/`res` objects) into an object with `type` and `parameters`, and conversely, formatting such an object back into a valid header string. This library is a foundational component for many HTTP servers and clients that need reliable content negotiation, differentiating itself through its minimalist API and strict RFC compliance without unnecessary abstractions.

http-networkingserialization
npm install content-type
github ↗package ↗
INSTALL
IMPORT
SIG · CONTENT-TYPE
C
content-type
http-networkingjavascriptv1.0.5
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.

contentType
✓ import * as contentType from 'content-type';
✗ const contentType = require('content-type');
CommonJS is shown in documentation; for ESM, use `import * as` as it exports a module object with named functions.
parse
✓ import { parse } from 'content-type';
✗ import contentType from 'content-type'; // Then contentType.parse()
While `contentType.parse` works with the `* as` import, named imports directly import the function. `content-type` does not export a default.
format
✓ import { format } from 'content-type';
✗ import contentType from 'content-type'; // Then contentType.format()
Similar to `parse`, `format` is a named export. Direct named import is preferred for clarity and tree-shaking.

This quickstart demonstrates parsing Content-Type headers from strings and simulated HTTP requests, and formatting objects back into header strings.

import { parse, format } from 'content-type'; import http from 'http'; // Example 1: Parsing a Content-Type string try { const headerString = 'text/html; charset=utf-8; boundary=xyz'; const parsed = parse(headerString); console.log('Parsed string:', parsed); // { type: 'text/html', parameters: { charset: 'utf-8', boundary: 'xyz' } } } catch (error) { console.error('Error parsing string:', error.message); } // Example 2: Formatting an object to a Content-Type string try { const objToFormat = { type: 'application/json', parameters: { charset: 'utf-8' } }; const formatted = format(objToFormat); console.log('Formatted object:', formatted); // 'application/json; charset=utf-8' } catch (error) { console.error('Error formatting object:', error.message); } // Example 3: Parsing from an incoming HTTP request (simulated) const server = http.createServer((req, res) => { req.headers['content-type'] = 'application/x-www-form-urlencoded; encoding=UTF-8'; try { const parsedReqHeader = parse(req); console.log('Parsed from request:', parsedReqHeader); res.writeHead(200, { 'Content-Type': format({ type: 'text/plain', parameters: { charset: 'utf-8' } }) }); res.end('Content-Type processed'); } catch (error) { console.error('Error parsing request content-type:', error.message); res.writeHead(400, { 'Content-Type': 'text/plain' }); res.end('Invalid Content-Type'); } }); server.listen(3000, () => { console.log('Server listening on http://localhost:3000'); server.close(); // Close immediately for quickstart example });
Debug
Known issues
gotchaThe `parse` function throws a `TypeError` if the input string is `null`, `undefined`, or an invalid Content-Type header format. Always wrap calls to `parse` in a `try...catch` block when dealing with potentially unreliable input, such as user-provided headers or network data.
fix
```javascript
try {
  const parsed = contentType.parse(headerValue);
  // ... use parsed object
} catch (error) {
  if (error instanceof TypeError) {
    console.error('Invalid Content-Type header:', error.message);
    // Handle invalid header, e.g., return 400 Bad Request
  } else {
    throw error;
  }
}
```
affects: >=1.0.0
gotchaWhen parsing from `req` or `res` objects, `contentType.parse(req)` is a shortcut for `contentType.parse(req.headers['content-type'])`. If the `Content-Type` header is entirely missing from the `req.headers` object, this will result in a `TypeError` as `undefined` is passed to the underlying parsing logic. Ensure the header exists if you expect to parse it.
fix
```javascript
const header = req.headers['content-type'];
if (header) {
  try {
    const parsed = contentType.parse(header);
    // ...
  } catch (error) {
    // Handle invalid format
  }
} else {
  console.warn('Content-Type header is missing.');
  // Handle missing header explicitly
}
```
affects: >=1.0.0
breakingVersion 1.0.0 was an initial implementation derived from `media-typer@0.3.0`. While intended to be a direct replacement for `media-typer`'s Content-Type specific features, users migrating from `media-typer` should verify their parsing and formatting logic, especially regarding error handling and edge cases, as the internal implementation changed.
fix
Review existing usage of `media-typer` and ensure `content-type` provides equivalent functionality and handles error conditions identically. Specifically check how invalid input strings are handled, as `content-type` consistently throws `TypeError`.
affects: =1.0.0
Errors
Common errors & fixes
TypeError: argument string is required
The `parse` function was called without an argument or with `null`/`undefined`.
fix
Ensure that a non-empty string is always passed to `contentType.parse()`. If parsing from `req.headers['content-type']`, explicitly check if the header exists before calling parse.
TypeError: invalid media type
The string provided to `parse` does not conform to a valid HTTP Content-Type header format.
fix
Verify the input string's syntax. It should follow the `type/subtype; parameter=value` structure. For example, `text/html`, `application/json; charset=utf-8` are valid, while `html` or `application/json;` (with trailing semicolon) might be invalid.
TypeError: invalid type
When using `contentType.format(obj)`, the `obj.type` property is missing, `null`, `undefined`, or not a valid media type string.
fix
Ensure the object passed to `contentType.format()` has a `type` property which is a valid media type string (e.g., `'application/json'`, `'text/plain'`).
Upgrade
Version history
1.0.5latest on npm
Audit
Dependencies

No dependency data recorded yet.

Agent activity
17 hits · last 30 days
node
16
OpenAI (training)
1
Resources
githubhttps://github.com/jshttp/content-type ↗
packagehttps://www.npmjs.com/package/content-type ↗
content-type — npm install content-type · libregistry