2.0.1 • Public • Published


Simple module to lookup the base format of HTTP response bodies from the content-type header. This module helps disambiguate the nature of the content, especially between text/* and application/*. The basic seven content type bases as defined RFC1341 are:

  • text
  • multipart
  • message
  • image
  • audio
  • video
  • application

However, from the content-type base, it is not easy to determine which formats are exactly "textual" in nature. For example, "text/json" as well as "application/json" are textual. This module disambiguates the same by maintaining a database of textual contents served over "application/*" content types.


npm install mime-format --save-dev;
var mimeFormat = require('mime-format');
console.log(mimeFormat.lookup('application/xml; charset=gBk'));
// outputs
// {
//   "type": "text",
//   "format": "xml"
//   "charset": "gBk"
// }

How to handle unlisted (not in db) content types?

When the content type is not in internal db, it looks for keywords in content type for best match. Under those circumstances, you will see a guessed: true property returned. In case even guess failed, you get unknown: true and format: 'raw' will be sent.

If the contentType argument is not a string, then the detection is attempted by typecasting it to String.

What is format?

Format is a secondary information for type: 'text' and 'embed. For texts, the format highlights what syntax the text is in. Additionally, it doubles up to let you know text was not detected by returning value raw. For most cases this is redundant.

List of types:

  • text
  • image
  • audio
  • video
  • embed
  • message
  • multipart
  • unknown

List of formats:

  • audio
  • video
  • image
  • plain
  • jsonp
  • json
  • xml
  • html
  • yaml
  • vml
  • webml
  • script
  • raw

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npm i mime-format

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