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JavaScript

import {
MIN_LENGTH_FOR_NSN,
VALID_DIGITS,
VALID_PUNCTUATION,
PLUS_CHARS
} from '../constants.js'
import createExtensionPattern from './extension/createExtensionPattern.js'
// Regular expression of viable phone numbers. This is location independent.
// Checks we have at least three leading digits, and only valid punctuation,
// alpha characters and digits in the phone number. Does not include extension
// data. The symbol 'x' is allowed here as valid punctuation since it is often
// used as a placeholder for carrier codes, for example in Brazilian phone
// numbers. We also allow multiple '+' characters at the start.
//
// Corresponds to the following:
// [digits]{minLengthNsn}|
// plus_sign*
// (([punctuation]|[star])*[digits]){3,}([punctuation]|[star]|[digits]|[alpha])*
//
// The first reg-ex is to allow short numbers (two digits long) to be parsed if
// they are entered as "15" etc, but only if there is no punctuation in them.
// The second expression restricts the number of digits to three or more, but
// then allows them to be in international form, and to have alpha-characters
// and punctuation. We split up the two reg-exes here and combine them when
// creating the reg-ex VALID_PHONE_NUMBER_PATTERN itself so we can prefix it
// with ^ and append $ to each branch.
//
// "Note VALID_PUNCTUATION starts with a -,
// so must be the first in the range" (c) Google devs.
// (wtf did they mean by saying that; probably nothing)
//
const MIN_LENGTH_PHONE_NUMBER_PATTERN = '[' + VALID_DIGITS + ']{' + MIN_LENGTH_FOR_NSN + '}'
//
// And this is the second reg-exp:
// (see MIN_LENGTH_PHONE_NUMBER_PATTERN for a full description of this reg-exp)
//
export const VALID_PHONE_NUMBER =
'[' + PLUS_CHARS + ']{0,1}' +
'(?:' +
'[' + VALID_PUNCTUATION + ']*' +
'[' + VALID_DIGITS + ']' +
'){3,}' +
'[' +
VALID_PUNCTUATION +
VALID_DIGITS +
']*'
// This regular expression isn't present in Google's `libphonenumber`
// and is only used to determine whether the phone number being input
// is too short for it to even consider it a "valid" number.
// This is just a way to differentiate between a really invalid phone
// number like "abcde" and a valid phone number that a user has just
// started inputting, like "+1" or "1": both these cases would be
// considered `NOT_A_NUMBER` by Google's `libphonenumber`, but this
// library can provide a more detailed error message — whether it's
// really "not a number", or is it just a start of a valid phone number.
const VALID_PHONE_NUMBER_START_REG_EXP = new RegExp(
'^' +
'[' + PLUS_CHARS + ']{0,1}' +
'(?:' +
'[' + VALID_PUNCTUATION + ']*' +
'[' + VALID_DIGITS + ']' +
'){1,2}' +
'$'
, 'i')
export const VALID_PHONE_NUMBER_WITH_EXTENSION =
VALID_PHONE_NUMBER +
// Phone number extensions
'(?:' + createExtensionPattern() + ')?'
// The combined regular expression for valid phone numbers:
//
const VALID_PHONE_NUMBER_PATTERN = new RegExp(
// Either a short two-digit-only phone number
'^' +
MIN_LENGTH_PHONE_NUMBER_PATTERN +
'$' +
'|' +
// Or a longer fully parsed phone number (min 3 characters)
'^' +
VALID_PHONE_NUMBER_WITH_EXTENSION +
'$'
, 'i')
// Checks to see if the string of characters could possibly be a phone number at
// all. At the moment, checks to see that the string begins with at least 2
// digits, ignoring any punctuation commonly found in phone numbers. This method
// does not require the number to be normalized in advance - but does assume
// that leading non-number symbols have been removed, such as by the method
// `extract_possible_number`.
//
export default function isViablePhoneNumber(number) {
return number.length >= MIN_LENGTH_FOR_NSN &&
VALID_PHONE_NUMBER_PATTERN.test(number)
}
// This is just a way to differentiate between a really invalid phone
// number like "abcde" and a valid phone number that a user has just
// started inputting, like "+1" or "1": both these cases would be
// considered `NOT_A_NUMBER` by Google's `libphonenumber`, but this
// library can provide a more detailed error message — whether it's
// really "not a number", or is it just a start of a valid phone number.
export function isViablePhoneNumberStart(number) {
return VALID_PHONE_NUMBER_START_REG_EXP.test(number)
}