docs: function e164(value, country_code, metadata)
  {
  	if (!value)
  	{
  		return undefined
  	}
  
  	// If the phone number is being input in an international format
  	if (value[0] === '+')
  	{
  		// If it's just the `+` sign
  		if (value.length === 1)
  		{
  			return undefined
  		}
  
  		// If there are some digits, the `value` is returned as is
  		return value
  	}
  
  	// For non-international phone number a country code is required
  	if (!country_code)
  	{
  		return undefined
  	}
  
  	// The phone number is being input in a country-specific format
  
  	const partial_national_number = parse_partial_number(value, country_code).national_number
  
  	if (!partial_national_number)
  	{
  		return undefined
  	}
  
  	// The value is converted to international plaintext
  	return format(partial_national_number, country_code, 'International_plaintext', metadata)
  }