negapi

negapi helps with content negotiation by selecting the most appropriate media type for a response based on a request’s Accept header.

Constructing a media type set takes exponential space and time on the highest number of parameters for a type. That number is typically 0, but if something significantly larger is required, this module may not be a good choice. Matching an Accept header against the set takes O(n log n + kn) time, where n is the number of ranges in the header and k is the number of distinct parameter names in the type set.

Usage

const negapi = require('negapi');

const types = new negapi.MediaTypeSet([
    new negapi.MediaType('text', 'plain', { format: 'flowed' }),
    new negapi.MediaType('application', 'json'),
    new negapi.MediaType('image', 'png'),
]);

const image = types.select('image/*, */*;q=0.5');
console.log(image.subtype);  // png

const text = types.select('text/plain');
console.log(text.get('format'));  // flowed

const none = types.select('*/*;q=0');
console.log(none);  // null

API

new MediaType(type, subtype, [parameters])

Creates a media type with the given type (string), subtype (string), and parameters (object with parameters as properties). In text/plain; format=flowed, the type is 'text', the subtype is 'plain', and the parameters are { format: 'flowed' }.

MediaType#type

The type, as a string.

MediaType#subtype

The subtype, as a string.

MediaType#get(name)

Gets the lowercase value of a parameter by name, or null if the parameter doesn’t exist. The name is case-insensitive.

new MediaTypeSet(types)

Creates a set of media types. types is an array of MediaTypes ordered by descending preference.

MediaTypeSet#select(accept)

Selects the most client-preferred MediaType of the MediaTypeSet according to the provided Accept header, or null if no type is acceptable.