code: function getTimeIntervalMeasurementUnits(localeData, restrictedSetOfUnits)
  {
  	// All available time interval measurement units.
  	let units = Object.keys(localeData)
  
  	// If only a specific set of available
  	// time measurement units can be used.
  	if (restrictedSetOfUnits) {
  		// Reduce available time interval measurement units
  		// based on user's preferences.
  		units = restrictedSetOfUnits.filter(_ => units.indexOf(_) >= 0)
  	}
  
  	// Stock `Intl.RelativeTimeFormat` locale data doesn't have "now" units.
  	// So either "now" is present in extended locale data
  	// or it's taken from ".second.current".
  	if ((!restrictedSetOfUnits || restrictedSetOfUnits.indexOf('now') >= 0) &&
  		units.indexOf('now') < 0) {
  		if (localeData.second.current) {
  			units.unshift('now')
  		}
  	}
  
  	return units
  }
docs: Get available time interval measurement units.