func init()

in phonenumbers.go [3321:3371]
31 lines of code
10 McCabe index (conditional complexity)

func init() {
	// load our regions
	regionMap, err := loadIntStringArrayMap(gen.RegionData)
	if err != nil {
		panic(err)
	}
	countryCodeToRegion = regionMap.Map

	// then our metadata
	err = loadMetadataFromFile("US", 1)
	if err != nil {
		panic(err)
	}

	for eKey, regionCodes := range countryCodeToRegion {
		// We can assume that if the county calling code maps to the
		// non-geo entity region code then that's the only region code
		// it maps to.
		if len(regionCodes) == 1 && REGION_CODE_FOR_NON_GEO_ENTITY == regionCodes[0] {
			// This is the subset of all country codes that map to the
			// non-geo entity region code.
			countryCodesForNonGeographicalRegion[eKey] = true
		} else {
			// The supported regions set does not include the "001"
			// non-geo entity region code.
			for _, val := range regionCodes {
				supportedRegions[val] = true
			}
		}

		supportedCallingCodes[eKey] = true
	}
	// If the non-geo entity still got added to the set of supported
	// regions it must be because there are entries that list the non-geo
	// entity alongside normal regions (which is wrong). If we discover
	// this, remove the non-geo entity from the set of supported regions
	// and log (or not log).
	delete(supportedRegions, REGION_CODE_FOR_NON_GEO_ENTITY)

	for _, val := range countryCodeToRegion[NANPA_COUNTRY_CODE] {
		writeToNanpaRegions(val, struct{}{})
	}

	// Create our sync.Onces for each of our languages for carriers
	for lang := range gen.CarrierData {
		carrierOnces[lang] = &sync.Once{}
	}
	for lang := range gen.GeocodingData {
		geocodingOnces[lang] = &sync.Once{}
	}
}