What is type-is?
The type-is npm package is used to determine the MIME type of the content represented by a request or response object. It can check if the content type matches any of the given MIME types, which can be useful for handling requests in web applications, especially when dealing with REST APIs or any other HTTP-based interfaces.
What are type-is's main functionalities?
Check content type
This feature allows you to check if a given content type matches one of the specified MIME types. In the code sample, it checks if 'image/png' is an image MIME type.
const typeis = require('type-is');
const contentType = 'image/png';
const result = typeis.is(contentType, ['image/*']); // returns 'image/png'
Determine if request has body
This feature checks if the request object has a body by inspecting the 'Content-Type' header.
const typeis = require('type-is');
const req = { headers: { 'content-type': 'text/html' } };
const hasBody = typeis.hasBody(req); // returns true
Determine the type of request
This feature determines the type of the request by checking if the 'Content-Type' header matches any of the provided MIME types.
const typeis = require('type-is');
const req = { headers: { 'content-type': 'application/json' } };
const result = typeis(req, ['json', 'urlencoded', 'multipart']); // returns 'json'
Other packages similar to type-is
mime-types
The mime-types package is similar to type-is in that it provides functionality for looking up MIME types based on file extensions and vice versa. However, it does not directly deal with request objects and is more focused on the mapping between MIME types and file extensions.
content-type
The content-type package is used to parse and format 'Content-Type' headers. Unlike type-is, it does not provide methods to check if a request or response matches a specific content type, but it can be used to construct and deconstruct 'Content-Type' headers.
accepts
The accepts package is designed to deal with the HTTP Accept header, allowing servers to negotiate content type with clients. It is similar to type-is in that it helps determine the type of content, but it focuses on what the client can accept, rather than what the server is receiving or sending.
type-is
Infer the content-type of a request.
Install
$ npm install type-is
API
var http = require('http')
var is = require('type-is')
http.createServer(function (req, res) {
is(req, ['text/*'])
})
type = is(request, types)
request
is the node HTTP request. types
is an array of types.
is(req, ['json'])
is(req, ['html', 'json'])
is(req, ['application/*'])
is(req, ['application/json'])
is(req, ['html'])
Each type can be:
- An extension name such as
json
. This name will be returned if matched. - A mime type such as
application/json
. - A mime type with a wildcard such as
*/json
or application/*
. The full mime type will be returned if matched - A suffix such as
+json
. This can be combined with a wildcard such as */vnd+json
or application/*+json
. The full mime type will be returned if matched.
false
will be returned if no type matches.
Examples
Example body parser
var is = require('type-is');
var parse = require('body');
var busboy = require('busboy');
function bodyParser(req, res, next) {
var hasRequestBody = 'content-type' in req.headers
|| 'transfer-encoding' in req.headers;
if (!hasRequestBody) return next();
switch (is(req, ['urlencoded', 'json', 'multipart'])) {
case 'urlencoded':
break
case 'json':
break
case 'multipart':
break
default:
}
}
License
The MIT License (MIT)
Copyright (c) 2013 Jonathan Ong me@jongleberry.com
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.