@becquerel/content-negotiator

HTTP content negotiation library.

Install

$ npm install --save @becquerel/content-negotiator  # Or alternately: `yarn add @becquerel/content-negotiator`

Usage

const ContentNegotiator = require('@becquerel/content-negotiator');

let acceptHeader = 'text/plain; q=0.5, text/html, text/x-dvi; q=0.8, text/x-c';
let negotiator = new ContentNegotiator(acceptHeader);

/**
 * Use the `.prefer()` method to check if a media type is the preferred type of
 * the requester. You can also use "shorthand types" for the following
 * predefined types:
 *
 *     {
 *         atom: 'atom+xml',
 *         css: 'text/css',
 *         csv: 'text/csv',
 *         html: 'text/html',
 *         javascript: 'application/javascript',
 *         jcard: 'application/vcard+json',
 *         json: 'application/json',
 *         jsonld: 'application/ld+json',
 *         markdown: 'text/markdown',
 *         text: 'text/plain',
 *         vcard: 'text/vcard'
 *     };
 */
negotiator.prefers('text/html');  // > true
negotiator.prefers('html');       // > true
negotiator.prefers('text/plain'); // > false

/**
 * Alternately you can read the `.preferred` property to obtain the requester's
 * most desired media type. It returns an instance of the `MediaType` class.
 */
negotiator.preferred; // > MediaType { type: 'text', subtype: 'html', parameters: { q: 1 }, specificity: 2 }

/**
 * Also, if you would prefer the textual representation of the preferred media
 * type you can simply call the `MediaType.prototype.toString()` method.
 */
negotiator.preferred.toString(); // > 'text/html'

/**
 * The `.mediaRange` property contains a quality sorted array of the desired
 * media types.
 */
negotiator.mediaRange; // > ['text/html', 'text/x-c', 'text/x-dvi', 'text/plain']

Testing

$ npm test  # Or alternately: `yarn test`

Reference

• Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content § 5.3: Content Negotiation

License

The MIT License (Expat). See the license file for details.