func FormatNationalNumberWithCarrierCode()

in phonenumbers.go [1221:1248]

• 22 lines of code
• 2 McCabe index (conditional complexity)

func FormatNationalNumberWithCarrierCode(number *PhoneNumber, carrierCode string) string {
	countryCallingCode := int(number.GetCountryCode())
	nationalSignificantNumber := GetNationalSignificantNumber(number)
	if !hasValidCountryCallingCode(countryCallingCode) {
		return nationalSignificantNumber
	}
	// Note GetRegionCodeForCountryCode() is used because formatting
	// information for regions which share a country calling code is
	// contained by only one region for performance reasons. For
	// example, for NANPA regions it will be contained in the metadata for US.
	regionCode := GetRegionCodeForCountryCode(countryCallingCode)
	// Metadata cannot be null because the country calling code is valid.
	metadata := getMetadataForRegionOrCallingCode(countryCallingCode, regionCode)

	formattedNumber := NewBuilder(nil)
	formattedNumber.WriteString(
		formatNsnWithCarrier(
			nationalSignificantNumber,
			metadata,
			NATIONAL,
			carrierCode))
	maybeAppendFormattedExtension(number, metadata, NATIONAL, formattedNumber)
	prefixNumberWithCountryCallingCode(
		countryCallingCode,
		NATIONAL,
		formattedNumber)
	return formattedNumber.String()
}