@desource/phone-mask

Core TypeScript library for international phone number masking with Google's libphonenumber data

Framework-agnostic phone masking library that stays up-to-date with Google's libphonenumber database.

✨ Features

• 🌍 240+ countries with accurate masks and dialing codes
• 🔄 Auto-synced from Google's libphonenumber
• 🪶 Tiny — 11.2 KB minified, 5.1 KB gzipped
• 🌳 Tree-shakeable — import only what you need
• 🔧 TypeScript — fully typed
• 🎯 Zero dependencies

📦 Installation

npm install @desource/phone-mask
# or
yarn add @desource/phone-mask
# or
pnpm add @desource/phone-mask

🚀 Quick Start

Basic Formatting

import { MasksBaseMap, MasksMap, formatDigitsWithMap } from '@desource/phone-mask';

// Get US mask with country code prefix
const prefixUsMask = MasksBaseMap.US;
// ["+1 ###-###-####"]

// Format digits
const result = formatDigitsWithMap(prefixUsMask[0], '2025551234');
console.log(result.display); // "+1 202-555-1234"
console.log(result.map); // [-1, -1, -1, 0, 1, 2, -1, 3, 4, 5, -1, 6, 7, 8, 9]

// Get US mask without country code prefix
const usMask = MasksMap.US.mask;
// ["###-###-####"]

// Format digits without country code
const resultNoCode = formatDigitsWithMap(usMask[0], '2025551234');
console.log(resultNoCode.display); // "202-555-1234"
console.log(resultNoCode.map); // [0, 1, 2, -1, 3, 4, 5, -1, 6, 7, 8, 9]

Working with Country Data

import { MasksFullMapEn, type MaskFull } from '@desource/phone-mask';

// Access country data
const us = MasksFullMapEn.US;

console.log(us.name); // "United States"
console.log(us.code); // "+1"
console.log(us.mask); // ["###-###-####"]
console.log(us.flag); // "🇺🇸"

Multiple Mask Variants

Some countries have multiple mask formats:

import { MasksFullMapEn } from '@desource/phone-mask';

const gb = MasksFullMapEn.GB;
console.log(gb.mask);
// [
//   "### ### ####",
//   "#### ######",
//   "## #### ####"
// ]

Localized Country Names

import { MasksFullMap } from '@desource/phone-mask';

// Get localized names
const germanMap = MasksFullMap('de');
console.log(germanMap.US.name); // "Vereinigte Staaten"

const frenchMap = MasksFullMap('fr');
console.log(frenchMap.US.name); // "États-Unis"

Utility Functions

import { countPlaceholders, removeCountryCodePrefix, pickMaskVariant, extractDigits } from '@desource/phone-mask';

// Count placeholder digits
const count = countPlaceholders('+1 ###-###-####');
// 10

// Remove country code prefix
const stripped = removeCountryCodePrefix('+1 ###-###-####');
// "###-###-####"

// Pick best mask variant for digit count
const variants = ['+44 ### ### ####', '+44 #### ######'];
const best = pickMaskVariant(variants, 11);
// "+44 #### ######"

// Extract only digits from string
const digits = extractDigits('+1 (202) 555-1234');
// "12025551234"

Validate Number Against Country Rules

Use createPhoneFormatter() to validate length against a specific country's mask variants.

import {
  MasksFullMapEn,
  createPhoneFormatter,
  extractDigits,
  removeCountryCodePrefix,
  type CountryKey
} from '@desource/phone-mask';

function validateForCountry(input: string, id: CountryKey) {
  const country = MasksFullMapEn[id];
  if (!country) {
    return {
      digits: '',
      display: '',
      isComplete: false
    };
  }

  const formatter = createPhoneFormatter({ ...country, id });
  const inputWithoutCode = removeCountryCodePrefix(input);
  const digits = extractDigits(inputWithoutCode, formatter.getMaxDigits());

  return {
    digits,
    display: formatter.formatDisplay(digits),
    isComplete: formatter.isComplete(digits)
  };
}

validateForCountry('+1 (202) 555-1234', 'US');
// { digits: "2025551234", display: "202-555-1234", isComplete: true }

Raw Digits for Backend Processing

Use raw digits for storage and transport. Keep formatting on the client only.

import {
  MasksFullMapEn,
  createPhoneFormatter,
  extractDigits,
  removeCountryCodePrefix,
  type CountryKey
} from '@desource/phone-mask';

function buildPhonePayload(input: string, id: CountryKey) {
  const country = MasksFullMapEn[id];
  if (!country) return null;

  const formatter = createPhoneFormatter({ ...country, id });
  const inputWithoutCode = removeCountryCodePrefix(input);
  const localDigits = extractDigits(inputWithoutCode, formatter.getMaxDigits());

  return {
    country: id,
    phoneDigits: localDigits, // canonical backend field
    phoneE164: `${country.code}${localDigits}` // optional: with dialing prefix
  };
}

Custom Regex + Metadata (Regional/Carrier Prefixes)

Combine Phone Mask metadata with region-specific regex rules:

import {
  MasksFullMapEn,
  createPhoneFormatter,
  extractDigits,
  removeCountryCodePrefix,
  type CountryKey
} from '@desource/phone-mask';

const tenantCarrierRules: Partial<Record<CountryKey, RegExp>> = {
  BR: /^(11|21|31)\d{8,9}$/,
  IN: /^(98|99)\d{8}$/
};

function validateWithCarrierRule(input: string, id: CountryKey): boolean {
  const country = MasksFullMapEn[id];
  if (!country) return false;

  const formatter = createPhoneFormatter({ ...country, id });
  const inputWithoutCode = removeCountryCodePrefix(input);
  const digits = extractDigits(inputWithoutCode, formatter.getMaxDigits());
  const carrierRule = tenantCarrierRules[id];

  if (!formatter.isComplete(digits)) return false;
  return carrierRule ? carrierRule.test(digits) : true;
}

Multi-tenant: tenantId Default Country + Tenant-specific Validation Rules

import {
  MasksFullMapEn,
  createPhoneFormatter,
  extractDigits,
  removeCountryCodePrefix,
  type CountryKey
} from '@desource/phone-mask';

type TenantPolicy = {
  defaultCountry: CountryKey;
  prefixRule?: RegExp;
};

const TENANT_POLICIES: Record<string, TenantPolicy> = {
  acme: { defaultCountry: 'US', prefixRule: /^(202|303)\d{7}$/ },
  globex: { defaultCountry: 'GB', prefixRule: /^7\d{9}$/ }
};

function createTenantPhoneService(tenantId: string) {
  const policy = TENANT_POLICIES[tenantId] ?? { defaultCountry: 'US' as const };
  const id = policy.defaultCountry;
  const country = MasksFullMapEn[id];
  const formatter = createPhoneFormatter({ ...country, id });

  return {
    defaultCountry: id,
    format(input: string) {
      const inputWithoutCode = removeCountryCodePrefix(input);
      const digits = extractDigits(inputWithoutCode, formatter.getMaxDigits());
      return formatter.formatDisplay(digits);
    },
    validate(input: string) {
      const inputWithoutCode = removeCountryCodePrefix(input);
      const digits = extractDigits(inputWithoutCode, formatter.getMaxDigits());
      const complete = formatter.isComplete(digits);
      const prefixOk = policy.prefixRule ? policy.prefixRule.test(digits) : true;
      return complete && prefixOk;
    }
  };
}

📖 API Reference

Types

// Country ISO 3166-1 alpha-2 code
type CountryKey = 'US' | 'GB' | 'DE' | ... // 240+ countries

// Mask interfaces
interface MaskBase {
  id: CountryKey;
  mask: Array<string>;
}
interface Mask extends MaskBase {
  code: string;
}
interface MaskWithFlag extends Mask {
  flag: string;
}
interface MaskFull extends MaskWithFlag {
  name: string;
}
type MaskBaseMap = Record<CountryKey, Array<string>>;
type MaskMap = Record<CountryKey, Omit<Mask, 'id'>>;
type MaskWithFlagMap = Record<CountryKey, Omit<MaskWithFlag, 'id'>>;
type MaskFullMap = Record<CountryKey, Omit<MaskFull, 'id'>>;

Core Exports

MasksBaseMap & MasksBase

Basic country masks including country code prefix (lightweight version):

const MasksBaseMap: MaskBaseMap;
const MasksBase: MaskBase[];

Use these to get raw masks with country code prefix. Note: some helper functions may expect masks without country code.

MasksMap & Masks

Masks with country code as separate property:

const MasksMap: MaskMap;
const Masks: Mask[];

MasksWithFlagMap & MasksWithFlag

Masks with country code and flag:

const MasksWithFlagMap: MaskWithFlagMap;
const MasksWithFlag: MaskWithFlag[];

MasksFullMapEn & MasksFullEn

Full country data with country names in English:

const MasksFullMapEn: MaskFullMap;
const MasksFullEn: MaskFull[];

MasksFullMap(locale: string) & MasksFull(locale: string)

Get full country data with localized country names:

function MasksFullMap(locale: string): MaskFullMap;
function MasksFull(locale: string): MaskFull[];

Supported locales: en, de, fr, es, it, pt, ru, zh, ja, ko, and more.

Utility Functions

// Count # placeholders in mask
function countPlaceholders(mask: string): number;

// Remove country code prefix from mask
function removeCountryCodePrefix(mask: string): string;

// Pick best mask variant for digit length
function pickMaskVariant(masks: string[], digitLength: number): string;

// Extract digits from any string
function extractDigits(value: string, maxLength?: number): string;

// Format digits according to template
function formatDigitsWithMap(value: string, digits: string): { display: string; map: number[] };

// Get flag emoji for country code
function getFlagEmoji(countryCode: CountryKey): string;

🎯 Use Cases

Custom Input Formatting

import { MasksFullMapEn, formatDigitsWithMap, extractDigits } from '@desource/phone-mask';

function formatPhoneInput(value: string, countryCode: string = 'US') {
  const country = MasksFullMapEn[countryCode];
  const mask = country?.mask[0];
  if (!mask) return value;

  const digits = extractDigits(value);

  return `${country.code} ${formatDigitsWithMap(mask, digits).display}`;
}

// Usage
const formatted = formatPhoneInput('2025551234', 'US');
// "+1 202-555-1234"

Phone Number Validation

import { MasksFullMapEn, countPlaceholders } from '@desource/phone-mask';

function isValidPhoneLength(digits: string, country: string): boolean {
  const masks = MasksFullMapEn[country]?.mask;
  if (!masks) return false;
  const validLengths = masks.map((m) => countPlaceholders(m));

  return validLengths.includes(digits.length);
}

// Usage
isValidPhoneLength('2025551234', 'US'); // true (10 digits)
isValidPhoneLength('202555', 'US'); // false (too short)

Building a Country Selector

import { MasksFullEn, type CountryKey, type MaskFull } from '@desource/phone-mask';

type CountryOption = Omit<MaskFull, 'mask'>;

function getCountryOptions(): CountryOption[] {
  return MasksFullEn.map((data) => ({
    id: data.id,
    name: data.name,
    code: data.code,
    flag: data.flag
  }));
}

// Usage
const countries = getCountryOptions();
// [
//   { id: 'US', name: 'United States', code: '+1', flag: '🇺🇸' },
//   { id: 'GB', name: 'United Kingdom', code: '+44', flag: '🇬🇧' },
//   ...
// ]

Getting Flag Emojis

import { getFlagEmoji } from '@desource/phone-mask';

// Get flag emoji for country code
const flag = getFlagEmoji('US'); // "🇺🇸"

🔄 Data Updates

The library syncs with Google's libphonenumber weekly via automated workflow. To update manually:

pnpm gen

This fetches the latest data and regenerates data.json. This updates generated metadata files used by the package (src/data.json, src/data.min.js, and src/data-types.ts).

📊 Bundle Size

Measured in a real consumer bundle:

| Export | Size (minified) | Gzipped | Brotli | | ------------------- | --------------: | ------: | ------: | | Full library | 11.20 KB | 5.10 KB | 4.39 KB | | MasksFullMapEn only | 5.77 KB | 2.68 KB | 2.17 KB | | Utilities only | 0.44 KB | 0.32 KB | 0.27 KB |

All exports are tree-shakeable — only import what you use!

🔗 Related Packages

• @desource/phone-mask-vue — Vue 3 component + composable + directive
• @desource/phone-mask-nuxt — Nuxt module
• @desource/phone-mask-react — React component + hook
• @desource/phone-mask-svelte — Svelte component + composable + action + attachment

📄 License

MIT © 2026 DeSource Labs

🤝 Contributing

See Contributing Guide