Configuration

spf.config holds the global configuration, initialized from SPF's defaults (original docs) with modern additions. Pass a partial config object to spf.init() (or spf.config.init()), or read and write individual keys at runtime.

Keys

Key	Default	Meaning
url-identifier	?spf=__type__	URL marker for SPF requests; __type__ is replaced by navigate | prefetch | load.
link-class	spf-link	Class marking an <a>/<form> as SPF-enabled.
nolink-class	spf-nolink	Class opting an element out of SPF handling.
cache-lifetime	600000 (10 min)	Maximum time (ms) a cache entry is valid.
cache-max	50	Maximum number of cache entries (LRU).
cache-unified	false	When true, cached responses are eligible for all navigations.
request-timeout	0	Request timeout in ms; 0 = none.
request-headers	null	Global request headers object.
reload-identifier	null	Reason parameter appended to fallback reload URLs.
navigate-limit	20	Max navigations per session (SPF behavior).
navigate-lifetime	86400000 (24 h)	Session lifetime in ms for the navigation limit.
animation-class	spf-animate	Class added to animated elements during view transitions.
animation-duration	425	View transition duration in ms (informational).
advanced-header-identifier	null	When set, identifies SPF requests via X-SPF-Request instead of the URL.
experimental-prefetch-mousedown	false	Prefetch on mousedown (SPF experiment).
prefetch-viewport	true	Prefetch spf-links as they enter the viewport.
speculation	prefetch	Speculation rules strategy: prefetch | prerender | none.

API

Method	Signature	Effect
init	(optConfig?: Partial<SpfConfig>) → void	Apply an optional config over the defaults.
get	(key) → value	Read a configuration value.
set	(key, value) → value	Set a configuration value; returns it.
clear	() → void	Reset to defaults.

Examples

spf.init({
  'url-identifier': '?spf=__type__',
  'cache-unified': true,
  speculation: 'prerender',
});

spf.config.set('prefetch-viewport', false);
const cls = spf.config.get('link-class'); // "spf-link"