RUM update: lux.js v300

22 February 2022

This is considered a major lux.js release and may contain some breaking changes.

Breaking changes

  • LUX.beaconMode has been removed.
  • LUX.getDebug() now returns a different format.

New features

  • The pathname of the current page is now tracked.
  • JavaScript error tracking can be disabled by setting LUX.errorTracking = false.
  • The maximum number of JavaScript errors tracked per page view can be controlled with LUX.maxErrors = <number>.
  • The maximum measure time can be controlled by setting LUX.maxMeasureTime = <number>. After this time, data collection will stop and the beacon will automatically be sent. This can be useful to prevent dynamic content like adverts from affecting your CLS and LCP scores late in the page load. The time is specified in milliseconds, and the default value is 60_000 (1 minute).


  • An unload handler is no longer used to track abandoned pages, except in legacy web browsers. The visibilitychange and pagehide events are used instead.
  • Developers who implement lux.js into a SPA by using = false can now opt-in to abandoned page tracking by setting LUX.sendBeaconOnPageHidden = true.

Bug fixes

  • Calling LUX.init() on the initial page load will no longer lose previously-captured data.