mPulse Boomerang

BOOMR.plugins. BFCache

Tracks Back-Forward Cache (BFCache) Navigations.

This plugin will send a "BFCache" beacon every time a BFCache navigation occurs, and will include the "Not Restored Reasons" when a Back-Forward navigation wasn't a BFCache navigation.

Beacon Parameters

This plugin adds the following parameters to the beacon:

  • http.initiator=bfcache: Designates this beacon as a BFCache navigation
  • rt.start=manual: Since this is a non-Page Load beacon
  • t_done: (Page Load Time) Set to the duration of the pageshow event
  • t_page: (Front End Time) Matches t_done and is set to the duration of the pageshow event
  • t_resp: (Back End Time) Set to 0
  • rt.tstart: (Event start) Set to the timestamp of the pageshow event
  • rt.end: (Event end) Set to the timestamp when the pageshow event fired
  • nt_nav_type: Set to Back-Forward Navigation (2)
  • pt.fcp: First Contentful Paint (from two requestAnimationFrames)
  • pt.lcp: Largest Contentful Paint (from two requestAnimationFrames)
  • bfc.nrr: BFCache "Not Restored Reasons" (list of strings) if BFCache wasn't possible (for regular Back-Forward navigations)

Methods

init(config)

Initializes the plugin.

Parameters:

Name Type Description
config object

Configuration

Properties
Name Type Description
minimumDwellTime number

Minimum dwell time before a beacon is sent

Returns:

BOOMR.plugins.BFCache The BFCache plugin for chaining

is_complete()

This plugin is always complete (ready to send a beacon)

Returns:

Type: boolean

true

notRestoredReasons()

Gets the page's Not Restored Reasons (if any), joined by a comma

Returns:

Type: string

String of Not Restored Reasons