function stripCountryCallingCode(number, country, metadata) {
	// Just an optimization, so that it
	// doesn't have to iterate through all country calling codes.
	if (country) {
		const countryCallingCodePrefix = '+' + getCountryCallingCode(country, metadata)

		// If `country` fits the actual `number`.
		if (number.length < countryCallingCodePrefix.length) {
			if (countryCallingCodePrefix.indexOf(number) === 0) {
				return ''
			}
		} else {
			if (number.indexOf(countryCallingCodePrefix) === 0) {
				return number.slice(countryCallingCodePrefix.length)
			}
		}
	}

	// If `country` doesn't fit the actual `number`.
	// Try all available country calling codes.
	for (const country_calling_code of Object.keys(metadata.country_calling_codes)) {
		if (number.indexOf(country_calling_code) === '+'.length) {
			return number.slice('+'.length + country_calling_code.length)
		}
	}

	return ''
}
Strips `+${countryCallingCode}` prefix from an E.164 phone number.
@param {string} number - (possibly incomplete) E.164 phone number.
@param {string?} country - A possible country for this phone number.
@param {object} metadata - `libphonenumber-js` metadata.
@return {string}