libphonenumber-metadata-generator/source/generate.js

Metadata generator for `libphonenumber-js`

import { parseString } from 'xml2js'

// Metadata format version.
import VERSION from './version.js'

// Should be the same as `DIGIT_PLACEHOLDER` in `libphonenumber-js`.
const DIGIT_PLACEHOLDER = 'x'

const PHONE_NUMBER_TYPES = [
	'premium_rate',
	'toll_free',
	'shared_cost',
	'voip',
	'personal_number',
	'pager',
	'uan',
	'voicemail',
	'fixed_line',
	'mobile'
]

// Parses `PhoneNumberMetadata.xml` file from Google's `libphonenumber` GitHub repository
// into a JSON structure, removing unused pieces of data in the process.
//
// -----------------------------------------------------------------------------------
//
// The following elements or attributes from "PhoneNumberMetadata.xml" are discarded
// in order to reduce code complexity and metadata file size:
//
// * `<references>` — a link to ITU (International Telecommunication Union)
//                    document describing phone numbering plan for a country
//
// * `<noInternationalDialling>` — who needs to input non-internationally-dialable phones
//
// * `<areaCodeOptional>` — we aren't in the XXth century,
//                          it's a globalized world, so write your
//                          phone numbers with area codes.
//
// * `<fixedLine>`, `<mobile>`, `<pager>`,
//   `<tollFree>`, `<premiumRate>`,
//   `<sharedCost>`, `<personalNumber>`,
//   `<voip>`, `<uan>`, `<voicemail>` — who needs that in the XXIst century.
//                                      just go mobile and stop talking nonsense.
//
// * `internationalPrefix`,
//   `preferredInternationalPrefix` — who needs to parse (or format) those weird
//                                    "internationally dialed" phone numbers
//                                    like "011 ..." in the USA.
//                                    this isn't XXth century, just use mobile phones.
//
// * `preferredExtnPrefix` — Localized " ext. ". E.g. ", доб. " instead of " ext. " for Russia.
//
// * `leadingZeroPossible` — (aka "italian leading zero")
//                           who needs to parse a phone number into an integer.
//                           just keep it as a string.
//
// * `carrierCodeFormattingRule` — only used in Brazil and Colombia
//                                 when dialing from within those countries
//                                 from mobile phones to fixed line phone numbers.
//                                 i guess brazilians and colombians
//                                 already know when to add those carrier codes
//                                 by themselves (and when not to add them)
//
// * `mobileNumberPortableRegion` — is only used to disable phone number type detection
//
// * `<possibleLengths>` — is a redundant field to speed up testing of
//                         whether a phone number format can be used to format
//                         a particular national (significant) phone number.
//
// -----------------------------------------------------------------------------------
//
// `libphonenumber/BuildMetadataFromXml.java` XML metadata parser was used as a reference.
// https://github.com/googlei18n/libphonenumber/blob/master/tools/java/common/src/com/google/i18n/phonenumbers/BuildMetadataFromXml.java
//
// -----------------------------------------------------------------------------------
//
// There are three XML metadata files in Google's `libphonenumber`:
//
//  * PhoneNumberMetadata.xml — core data, used both for parse/format and "as you type"
//
//  * PhoneNumberAlternateFormats.xml — alternative phone number formats.
//                                      is presumably used for parsing phone numbers
//                                      written in "alternative" formats.
//                                      is not used by "as you type"
//                                      presumably because of formats ambiguity
//                                      when combined with the core data.
//                                      this metadata is not used in this library
//                                      as there's no clear description on what to do with it
//                                      and how it works in the original `libphonenumber` code.
//
//  * ShortNumberMetadata.xml — emergency numbers, etc. not used in this library.
//
// -----------------------------------------------------------------------------------
//
// @returns
//
// {
// 	country_calling_codes:
// 	{
// 		'7': ['RU', 'KZ', ...],
// 		...
// 	},
// 	countries:
// 	{
// 		RU:
// 		{
// 			phone_code: "7",
// 			national_number_pattern: "[347-9]\\d{9}",
// 			national_prefix: "8",
// 			national_prefix_formatting_rule: "8 ($1)",
// 			national_prefix_is_optional_when_formatting: true,
// 			types:
// 			{
// 				fixed_line: "(?:3(?:0[12]|4[1-35-79]|5[1-3]|65|8[1-58]|9[0145])|4(?:01|1[1356]|2[13467]|7[1-5]|8[1-7]|9[1-689])|8(?:1[1-8]|2[01]|3[13-6]|4[0-8]|5[15]|6[1-35-79]|7[1-37-9]))\\d{7}",
// 				mobile: "9\\d{9}",
// 				...
// 			},
// 			examples:
// 			{
// 				fixed_line: '4955553535',
// 				mobile: '9991234567',
// 				...
// 			},
// 			formats:
// 			[{
// 				pattern: "([3489]\\d{2})(\\d{3})(\\d{2})(\\d{2})",
// 				leading_digits_patterns: ["[3489]"],
// 				format: "$1 $2-$3-$4"
// 			},
// 			...]
// 		},
// 		...
// 	}
// }
//
// `country_calling_codes` map is kinda redundant.
// Not sure why did I choose to place country phone codes
// into a separate structure inside metadata instead of generating it in runtime.
// One extra feature it gives though is it tells what's the
// "default" country for a given country phone code.
// E.g. for country phone code `1` the "default" country is "US"
// and therefore "US" is the first country code in the
// `country_calling_codes["1"]` list.
// The "default" country is the one other countries
// with the same country phone code inherit phone number formatting rules from.
// For example, "CA" (Canada) inhertis phone number formatting rules from "US".
//
// `country_calling_codes` data takes about 3 KiloBytes
// so it could kinda make sense to drop it from the metadata file
// replacing it with a "default" country flag (something like `1` for "yes").
// In that scenario `country_calling_codes` would be generated on startup.
// It would have to also provide an exported `getCountryPhoneCodes()` function
// which would take `metadata` and return `country_calling_codes` map
// because some people use that `country_calling_codes` map in their projects.
//
// On the other hand, having `country_calling_codes`
// prepopulated yields more elegance to the exports
// because if `country_calling_codes` wasn't part of metadata
// it would have to be computed somewhere in global scope
// therefore the modules wouldn't be strictly "pure"
// so maybe `country_calling_codes` stays as part of metadata.
//
export default function(xmlString, arg1, arg2, arg3, arg4) {
	// Convert legacy options being separate arguments
	// to new options being a single argument (object).
	let version
	let includedCountries
	let includeAllPhoneNumberTypes
	let includedPhoneNumberTypes
	let includePhoneNumberTypeExamples
	// When no arguments were passed (aside from metadata XML) then it's assumed to be a case of
	// new `options` object argument rather than a case of legacy parameters.
	// It is still possible that it's a case of legacy arguments which just aren't passed,
	// but in that case the only "breaking change" would be that phone number examples aren't present,
	// and the consuming application would notice that when attempting to access `examples` object properties
	// because a `TypeError` would be thrown: Cannot read properties of undefined (reading 'mobile').
	// Such "breaking change" would only be possible if someone used `generate()` function
	// without further minification via `compress()` function, so it wouldn't be the mainstream way
	// of using this package, because the mainstream way is the command-line-interface one, and it always minijfied,
	// and minification removes example phone numbers anyway, not to mention that it still passed the `extended: true/false` argument,
	// and also not to mention that the README of `generate()` function specifically instructs `version: number` argument to be passed.
	if (arg1 === undefined && arg2 === undefined && arg3 === undefined && arg4 === undefined) {
		arg1 = {}
	}
	// New options — object.
	if (isObject(arg1)) {
		// Validate `phoneNumberTypes` parameter.
		if (arg1.phoneNumberTypes && !arg1.withPhoneNumberTypes) {
			throw new Error('`phoneNumberTypes` parameter requires `withPhoneNumberTypes: true` parameter')
		}
		version = VERSION
		includedCountries = arg1.countries
		includeAllPhoneNumberTypes = arg1.withPhoneNumberTypes && !arg1.phoneNumberTypes
		includedPhoneNumberTypes = arg1.phoneNumberTypes
		includePhoneNumberTypeExamples = arg1.withPhoneNumberTypeExamples
	} else {
		// Legacy options — separate arguments.
		version = arg1
		includedCountries = arg2
		includeAllPhoneNumberTypes = arg3
		includedPhoneNumberTypes = arg4
		includePhoneNumberTypeExamples = true
	}

	// Validate `includedPhoneNumberTypes`
	if (includedPhoneNumberTypes) {
		for (const _type of includedPhoneNumberTypes) {
			if (PHONE_NUMBER_TYPES.indexOf(_type) < 0) {
				return Promise.reject(`Unknown phone number type: ${_type}`)
			}
		}
	}

	// Parse the XML metadata.
	// See: https://gitlab.com/catamphetamine/libphonenumber-js/blob/master/METADATA.md
	return parseXmlString(xmlString).then((xml) => {
		// https://github.com/googlei18n/libphonenumber/blob/master/resources/PhoneNumberMetadata.xml
		// https://github.com/googlei18n/libphonenumber/blob/master/resources/phonemetadata.proto
		// https://github.com/googlei18n/libphonenumber/blob/master/javascript/i18n/phonenumbers/phonenumberutil.js
		// https://github.com/googlei18n/libphonenumber/blob/master/javascript/i18n/phonenumbers/asyoutypeformatter.js

		const country_calling_code_to_countries = {}
		const countries = {}
		const nonGeographic = {}

		for (const territory of xml.phoneNumberMetadata.territories[0].territory) {
			// A two-letter country code
			const country_code = territory.$.id

			// Skip this country if it has not been explicitly included
			if (includedCountries) {
				if (Array.isArray(includedCountries)) {
					if (!includedCountries.includes(country_code)) {
						continue
					}
				} else {
					// Legacy argument type: `Set`.
					if (!includedCountries.has(country_code)) {
						continue
					}
				}
			}

			if (territory.$.nationalPrefixOptionalWhenFormatting) {
				throw new Error('`nationalPrefixOptionalWhenFormatting` encountered on a country level: uncomment the relevant code part below.')
			}

			// Country metadata
			const country = {
				// Phone code related fields:

				// Phone code for phone numbers in this country.
				//
				// E.g. `"1"` for both USA and Canada.
				//
				phone_code: territory.$.countryCode,

				// International Direct Dialing prefix.
				idd_prefix: territory.$.internationalPrefix,
				default_idd_prefix: territory.$.preferredInternationalPrefix,

				// Localized " ext. " prefix.
				ext: territory.$.preferredExtnPrefix,

				// In case of several countries
				// having the same country phone code,
				// these leading digits are the means
				// of classifying an international phone number
				// whether it belongs to a certain country.
				//
				// E.g. for Antigua and Barbuda
				// country phone code is `"1"` (same as USA)
				// and leading digits are `"268"`.
				//
				leading_digits: territory.$.leadingDigits,

				// The regular expression of all possible
				// national (significant) numbers for this country.
				national_number_pattern: territory.generalDesc[0].nationalNumberPattern[0].replace(/\s/g, ''),

				// National prefix related fields:

				// aka "trunk code".
				// This is the prefix prepended to a
				// national (significant) phone number
				// when dialed from within the country.
				// E.g. `0` for UK.
				national_prefix: territory.$.nationalPrefix,

				// In some (many) countries the national prefix
				// is not just a constant digit (like `0` in UK)
				// but can be different depending on the phone number
				// (and can be also absent for some phone numbers).
				//
				// So `national_prefix_for_parsing` is used when parsing
				// a national-prefixed (local) phone number
				// into a national significant phone number
				// extracting that possible national prefix out of it.
				//
				national_prefix_for_parsing : territory.$.nationalPrefixForParsing ? territory.$.nationalPrefixForParsing.replace(/\s/g, '') : undefined,

				// If `national_prefix_for_parsing` regular expression
				// contains "captured groups", then `national_prefix_transform_rule`
				// defines how the national-prefixed (local) phone number is
				// parsed into a national significant phone number.
				//
				// Pseudocode:
				//
				// national_prefix_pattern = regular_expression('^(?:' + national_prefix_for_parsing + ')')
				// national_significant_number = all_digits.replace(national_prefix_pattern, national_prefix_transform_rule)
				//
				// E.g. if a country's national numbers are 6-digit
				// and national prefix is always `0`,
				// then `national_prefix_for_parsing` could be `0(\d{6})`
				// and the corresponding `national_prefix_transform_rule` would be `$1`
				// (which is the default behaviour).
				//
				// Currently this feature is only used in
				// Argentina, Brazil, Mexico and San Marino
				// due to their messy telephone numbering plans.
				//
				// For example, mobile numbers in Argentina are written in two completely
				// different ways when dialed in-country and out-of-country
				// (e.g. 0343 15-555-1212 is exactly the same number as +54 9 3435 55 1212).
				// Therefore for Argentina `national_prefix_transform_rule` is `9$1`.
				//
				national_prefix_transform_rule: territory.$.nationalPrefixTransformRule,

				// Controls how national prefix is written
				// in a formatted local phone number.
				//
				// E.g. in Armenia national prefix is `0`
				// and `national_prefix_formatting_rule` is `($NP$FG)`
				// which means that a national significant phone number `xxxxxxxx`
				// matching phone number pattern `(\d{2})(\d{6})` with format `$1 $2`
				// is written as a local phone number `(0xx) xxxxxx`.
				//
				// As of 2026, this property seems to have been moved from country-wide level
				// to an individual `format` level.
				//
				national_prefix_formatting_rule: getNationalPrefixFormattingRule(territory.$.nationalPrefixFormattingRule, territory.$.nationalPrefix),

				// Is it possible that a national (significant)
				// phone number has leading zeroes?
				//
				// E.g. in Gabon some numbers start with a `0`
				// while the national prefix is also `0`
				// which is optional for mobile numbers.
				//
				// This seems to only be used for validating
				// possible formats in AsYouType formatter.
				//
				// national_prefix_is_optional_when_formatting: territory.$.nationalPrefixOptionalWhenFormatting ? Boolean(territory.$.nationalPrefixOptionalWhenFormatting) : undefined,

				// In some countries carrier code is required
				// to dial certain phone numbers.
				//
				// E.g. in Colombia calling to fixed line numbers
				// from mobile phones requires a carrier code when called within Colombia.
				// Or, for example, Brazilian fixed line and mobile numbers
				// need to be dialed with a carrier code when called within Brazil.
				// Without that, most of the carriers won't connect the call.
				//
				// As of 2026, this property seems to have been moved from country-wide level
				// to an individual `format` level.
				//
				domestic_carrier_code_formatting_rule: territory.$.carrierCodeFormattingRule,

				// These `types` will be discared later if they're not needed (which is most likely).
				// They're currently only used when there're multiple countries corresponding to the same calling code.
				// In such cases, it's not possible to determine the country of a phone number just by its "calling code" part,
				// and it has to be matched against each "candidate" country by either its `leading_digits` or by its `types` reg exps.
				//
				types: getPhoneNumberTypes(territory),

				// Will be filtered out during minification phase
				examples: includePhoneNumberTypeExamples ? get_phone_number_examples(territory) : undefined
			}

			// Check that national (significant) phone number pattern
			// is set for this country (no "default" value here)
			if (!country.national_number_pattern) {
				throw new Error(`"generalDesc.nationalNumberPattern" is missing for country ${country_code} metadata`)
			}

			// Check that an IDD prefix is always defined.
			if (country_code !== '001' && !country.idd_prefix) {
				throw new Error(`"generalDesc.internationalPrefix" is missing for country ${country_code} metadata`)
			}

			// // Check that a preferred IDD prefix is always defined if IDD prefix is a pattern.
			// if (country_code !== '001' && !isSingleIDDPrefix(country.idd_prefix) && !country.default_idd_prefix) {
			// 	throw new Error(`"generalDesc.preferredInternationalPrefix" is missing for country ${country_code} metadata`)
			// }

			// Some countries don't have `availableFormats` specified,
			// because those formats are inherited from the "main country for region":
			// all non-"main" countries inherit their formats from the "main" country for that region.
			if (territory.availableFormats) {
				country.formats = territory.availableFormats[0].numberFormat.map((number_format) => ({
					pattern: number_format.$.pattern,
					// There could be multiple `<leadingDigits/>` elements inside a given `<format/>` element.
					leading_digits_patterns: number_format.leadingDigits ? number_format.leadingDigits.map(leading_digits => leading_digits.replace(/\s/g, '')) : undefined,
					national_prefix_formatting_rule: getNationalPrefixFormattingRule(number_format.$.nationalPrefixFormattingRule, territory.$.nationalPrefix),
					national_prefix_is_optional_when_formatting: number_format.$.nationalPrefixOptionalWhenFormatting ? Boolean(number_format.$.nationalPrefixOptionalWhenFormatting) : undefined,
					format: number_format.format[0],
					international_format: number_format.intlFormat ? number_format.intlFormat[0] : undefined,
					domestic_carrier_code_formatting_rule: number_format.$.carrierCodeFormattingRule
				}))
				// Screw local-only formats
				.filter(format => format.international_format !== 'NA')

				// Sanity check (using no "default" for this field)
				for (const format of country.formats) {
					// Never happens
					if (!format.format) {
						throw new Error(`No phone number format "format" supplied for pattern ${format.pattern} for ${country_code}`)
					}
					// Never happens
					if (format.format.indexOf(DIGIT_PLACEHOLDER) >= 0) {
						throw new Error(`Phone number format "${format.format}" contains a reserved "${DIGIT_PLACEHOLDER}" symbol for pattern ${format.pattern} for ${country_code}`)
					}
				}
			}

			if (country_code === '001') {
				nonGeographic[country.phone_code] = country
				// Populate numbering plan possible lengths.
				populateNumberingPlanPossibleLengths(country)
			} else {
				// Add this country's metadata
				// to the metadata map.
				countries[country_code] = country

				// Register this country's "country phone code"
				if (!country_calling_code_to_countries[country.phone_code]) {
					country_calling_code_to_countries[country.phone_code] = []
				}

				// In case of several countries
				// having the same country phone code.
				//
				// E.g. for USA and Canada, USA is the
				// "main country for phone code 1".
				//
				// (maybe this field is not used at all
				//  in which case this field is to be removed)
				//
				if (territory.$.mainCountryForCode === "true") {
					country_calling_code_to_countries[country.phone_code].unshift(country_code)
				} else {
					country_calling_code_to_countries[country.phone_code].push(country_code)
				}
			}
		}

		// Some countries don't have `availableFormats` specified,
		// because those formats are meant to be copied from the "main country for region":
		// all non-"main" countries inherit their formats from the "main" country for that region.
		// If that's the case then `nationalPrefixFormattingRule` and
		// `nationalPrefixOptionalWhenFormatting` are also copied from the "main" region.
		// `nationalPrefix` itself though seems to be always present
		// even if it's the same for the "main" region.
		// Examples: "RU" and "KZ", "US" and "CA".
		for (const country_code of Object.keys(countries)) {
			const country = countries[country_code]
			const main_country_for_region_code = country_calling_code_to_countries[country.phone_code][0]
			if (main_country_for_region_code === country_code) {
				// Some countries like Saint Helena and Falkland Islands
				// ('AC', 'FK', 'KI', 'NU', 'SH', 'TA', ...)
				// don't have any phone number formats defined
				// and phone numbers are not formatted in those countries.
				if (!country.formats) {
					country.formats = []
				}
			}
			else {
				if (country.formats !== undefined) {
					throw new Error(`Country "${country_code}" is supposed to inherit formats from "${main_country_for_region_code}" but has its own formats defined.`)
				}
				if (country.national_prefix_formatting_rule !== undefined) {
					throw new Error(`Country "${country_code}" is supposed to inherit "national_prefix_formatting_rule" from "${main_country_for_region_code}" but has its own "national_prefix_formatting_rule" defined.`)
				}
				if (country.national_prefix_is_optional_when_formatting !== undefined) {
					throw new Error(`Country "${country_code}" is supposed to inherit "national_prefix_is_optional_when_formatting" from "${main_country_for_region_code}" but has its own "national_prefix_is_optional_when_formatting" defined.`)
				}
			}
		}

		// Turns out that `<generalDesc><nationalNumberPattern/></generalDesc>`
		// is not preemptive at all: it's too unspecific for the cases
		// when several countries correspond to the same country phone code
		// (e.g. NANPA: US, Canada, etc — all correspond to the same `1` country phone code).
		// For these cases all those bulky `<fixedLine/>`, `<mobile/>`, etc
		// patterns are required. Therefore retain them for these rare cases.
		//
		// This increases metadata size by 5 KiloBytes.
		//
		const visited_countries = {}
		for (const country_calling_code of Object.keys(country_calling_code_to_countries)) {
			const country_codes = country_calling_code_to_countries[country_calling_code]

			for (const country_code of country_codes) {
				if (visited_countries[country_code]) {
					continue
				}

				visited_countries[country_code] = true

				// Populate numbering plan possible lengths.
				populateNumberingPlanPossibleLengths(countries[country_code])

				if (countries[country_code].possible_lengths.length === 0) {
					throw new Error(`No \`possibleLengths\` are specified for country "${country_code}". That could become an issue because, for example, \`react-phone-number-input\` package relies on \`possibleLengths\` to always be specified.`)
				}
			}

			// `types` regular expressions are huge, and they're not only used to
			// determine phone number type, but also to determine which country
			// a phone number belongs to when there's an "ambiguity" situation,
			// i.e. when there're multiple countries sharing the same "calling code".
			//
			// For example, US and Canada share the same `+1` "calling code"
			// and it's not really possible to tell which one of them
			// owns a given `+1...` phone number until all their `types` regular exporessions
			// have been run.
			//
			// That means that `types` regular expresssions could only be omitted
			// when there're no multiple countries that share a given "calling code".
			//
			const allTypeRegExpsAreRequired = country_codes.length > 1

			if (!includeAllPhoneNumberTypes && !includedPhoneNumberTypes && !allTypeRegExpsAreRequired) {
				// console.log(`Won't include the regular expressions for different phone number types for country ${country_code} because it doesn't share its calling code with any other country, and, therefore, the regular expressions for different phone number types won't have to be used for country matching`)
				delete countries[country_codes[0]].types
				continue
			}

			for (const country_code of country_codes) {
				// Leading digits for a country are sufficient
				// to resolve the "calling code" ambiguity,
				// i.e. when multiple countries share the same "calling code".
				//
				// So retaining all phone number type regular expressions
				// is not required in this case.
				//
				if (!includeAllPhoneNumberTypes && !includedPhoneNumberTypes) {
					if (countries[country_code].leading_digits) {
						// console.log(`Won't include the regular expressions for different phone number types for country ${country_code} because even though it does share its calling code with other countries, it also has leading digits specified, and, therefore, the regular expressions for different phone number types won't have to be used for country matching`)
						delete countries[country_code].types
						continue
					}
				}

				// `types` will potentially be mutated
				const types = countries[country_code].types

				// Find duplicate regular expressions for types
				// and just discard such duplicate types
				// to reduce metadata size (by 5 KiloBytes).
				// Or retain regular expressions just for the
				// specified phone number types (if configured).
				for (const _type of PHONE_NUMBER_TYPES) {
					if (!types[_type]) {
						continue
					}
					// Retain regular expressions just for the
					// specified phone number types (if configured).
					if (includedPhoneNumberTypes) {
						if (Array.isArray(includedPhoneNumberTypes)) {
							if (!includedPhoneNumberTypes.includes(_type)) {
								delete types[_type]
							}
						} else {
							// Legacy argument type: `Set`.
							if (!includedPhoneNumberTypes.has(_type)) {
								delete types[_type]
							}
						}
					}
					// Remove redundant types
					// (other types having the same regular expressions as this one)
					else {
						// Sometimes fixed line pattern is the same as for mobile.
						if (
							types.fixed_line && types.mobile &&
							types.fixed_line.pattern === types.mobile.pattern
						) {
							types.mobile.pattern = ''
						}
					}
				}
			}
		}

		return {
			version,
			countries,
			country_calling_codes: country_calling_code_to_countries,
			nonGeographic
		}
	})
}

// Replaces $NP with national prefix and $FG with the first group ($1)
function getNationalPrefixFormattingRule(rule, national_prefix) {
	if (!rule) {
		return
	}
	// Replace $NP with national prefix and $FG with the first group ($1)
	return rule
		.replace('$NP', national_prefix)
		.replace('$FG', '$1')
}

// Extracts various phone number type patterns from country XML metadata
function getPhoneNumberTypes(territory) {
	return PHONE_NUMBER_TYPES.reduce((output, type) => {
		const camel_cased_type = underscoreToCamelCase(type)
		const pattern = territory[camel_cased_type] && territory[camel_cased_type][0].nationalNumberPattern[0].replace(/\s/g, '')
		const possible_lengths = territory[camel_cased_type] && territory[camel_cased_type][0].possibleLengths[0].$.national
		const possible_lengths_local = territory[camel_cased_type] && territory[camel_cased_type][0].possibleLengths[0].$.localOnly
		if (pattern) {
			output[type] = {
				pattern,
				possible_lengths,
				// possible_lengths_local
			}
		}
		return output
	},
	{})
}

// Extracts various phone number type examples from country XML metadata
function get_phone_number_examples(territory) {
	return PHONE_NUMBER_TYPES.reduce((output, type) => {
		const camel_cased_type = underscoreToCamelCase(type)
		const example = territory[camel_cased_type] && territory[camel_cased_type][0].exampleNumber[0]
		if (example) {
			output[type] = example
		}
		return output
	}, {})
}

function underscoreToCamelCase(string) {
	return string.replace(/(\_\w)/g, match => match[1].toUpperCase())
}

/**
* Parses a possible length string into a set of the integers that are covered.
*
* @param {string} possible_length_string - A string specifying the possible lengths of phone numbers. Follows
*     this syntax: ranges or elements are separated by commas, and ranges are specified in
*     [min-max] notation, inclusive. For example, [3-5],7,9,[11-14] should be parsed to
*     3,4,5,7,9,11,12,13,14.
* @return {Set}
*/
function parse_possible_lengths(possible_length_string) {
	if (possible_length_string.length === 0) {
		throw new TypeError('Empty possibleLength string found.')
	}

	const lengths = new Set()

	for (const length of possible_length_string.split(',')) {
		if (length.length == 0) {
			throw new TypeError(`Leading, trailing or adjacent commas in possible length string ${length}, these should only separate numbers or ranges.`)
		}

		if (length[0] === '[') {
			if (length[length.length - 1] !== ']') {
				throw new TypeError(`Missing end of range character in possible length string ${length}.`)
			}

			// Strip the leading and trailing [], and split on the -.
			const min_max = length.slice(1, length.length - 1).split('-').map(_ => parseInt(_))

			if (min_max.length !== 2) {
				throw new TypeError(`Ranges must have exactly one - character: missing for ${length}.`)
			}

			const [min, max] = min_max

			// We don't even accept [6-7] since we prefer the shorter 6,7 variant;
			// for a range to be in use the hyphen needs to replace at least one digit.
			if (max - min < 2) {
				throw new TypeError(`The first number in a range should be two or more digits lower than the second. Culprit possibleLength string: ${length}`)
			}

			for (let i = min; i <= max; i++) {
				if (lengths.has(i)) {
					throw new TypeError(`Duplicate length element found (${i}) in possibleLength string ${length}.`)
				}
				lengths.add(i)
			}
		}
		else {
			const i = parseInt(length)
			if (lengths.has(i)) {
				throw new TypeError(`Duplicate length element found (${i}) in possibleLength string ${length}.`)
			}
			lengths.add(i)
		}
	}

	return lengths
}

const areEqualArrays = (a1, a2) => a1.length === a2.length && a1.every((_, i) => _ === a2[i])

/**
 * Sets `metadata.possible_lengths` to a combination of `possible_length`s
 * of all types present in the numbering plan metadata.
 * @param  {object} metadata
 */
function populateNumberingPlanPossibleLengths(metadata) {
	const types = metadata.types

	const possible_lengths = new Set()
	const possible_lengths_local = new Set()

	for (const _type of Object.keys(types)) {
		const type_possible_lengths = parse_possible_lengths(types[_type].possible_lengths)
		for (const i of type_possible_lengths) {
			possible_lengths.add(i)
		}
		types[_type].possible_lengths = Array.from(type_possible_lengths)

		if (types[_type].possible_lengths_local) {
			const type_possible_lengths_local = parse_possible_lengths(types[_type].possible_lengths_local)
			for (const i of type_possible_lengths_local) {
				possible_lengths_local.add(i)
			}
			types[_type].possible_lengths_local = Array.from(type_possible_lengths_local)
		}
	}

	for (const i of possible_lengths_local) {
		if (possible_lengths.has(i)) {
			possible_lengths_local.delete(i)
		}
	}

	metadata.possible_lengths = Array.from(possible_lengths)
	metadata.possible_lengths.sort((a, b) => a - b)

	if (possible_lengths_local.size > 0) {
		metadata.possible_lengths_local = Array.from(possible_lengths_local)
		metadata.possible_lengths_local.sort((a, b) => a - b)
	}

	// Remove duplicates.
	for (const _type of Object.keys(types)) {
		if (areEqualArrays(types[_type].possible_lengths, metadata.possible_lengths)) {
			delete types[_type].possible_lengths
		}
		if (types[_type].possible_lengths_local && metadata.possible_lengths_local &&
			areEqualArrays(types[_type].possible_lengths_local, metadata.possible_lengths_local)) {
			delete types[_type].possible_lengths_local
		}
	}
}

function parseXmlString(xmlString) {
	return new Promise((resolve, reject) => {
		parseString(xmlString, (error, result) => {
			if (error) {
				return reject(error)
			}
			resolve(result)
		})
	})
}

const objectConstructor = {}.constructor
function isObject(object) {
  return object !== undefined && object !== null && object.constructor === objectConstructor
}