Return accepted charsets or best fit based on charsets.

Given Accept-Charset: utf-8, iso-8859-1;q=0.2, utf-7;q=0.5 an array sorted by quality is returned:

['utf-8', 'utf-7', 'iso-8859-1']

Return accepted encodings or best fit based on encodings.

Given Accept-Encoding: gzip, deflate an array sorted by quality is returned:

['gzip', 'deflate']

Return accepted languages or best fit based on langs.

Given Accept-Language: en;q=0.8, es, pt an array sorted by quality is returned:

['es', 'pt', 'en']

Check if the given type(s) is acceptable, returning the best match when true, otherwise undefined, in which case you should respond with 406 "Not Acceptable".

The type value may be a single mime type string such as "application/json", the extension name such as "json" or an array ["json", "html", "text/plain"]. When a list or array is given the best match, if any is returned.

Examples:

// Accept: text/html
this.types(['html']);
// => ["html"]

// Accept: text/*, application/json
this.types(['html']);
// => ["html"]
this.types(['text/html']);
// => ["text/html"]
this.types(['json', 'text']);
// => ["json"]
this.types(['application/json']);
// => ["application/json"]

// Accept: text/*, application/json
this.types(['image/png']);
this.types(['png']);
// => []

// Accept: text/*;q=.5, application/json
this.types(['html', 'json']);
// => ["json"]