Persian Tools

Iranian and Arabic input often arrives with three different numeral systems mixed together. These functions move between them and provide an autoConvertDigitsToEN helper that normalizes any input to English digits.

The three systems

System	Sample	Unicode range
English (Latin)	`0123456789`	U+0030 – U+0039
Persian (Farsi)	`۰۱۲۳۴۵۶۷۸۹`	U+06F0 – U+06F9
Arabic-Indic	`٠١٢٣٤٥٦٧٨٩`	U+0660 – U+0669

These are disjoint ranges — Persian digits ≠ Arabic-Indic digits despite casual users using the names interchangeably.

Converters

import {
	digitsEnToFa,
	digitsEnToAr,
	digitsFaToEn,
	digitsFaToAr,
	digitsArToEn,
	digitsArToFa,
	autoConvertDigitsToEN,
} from "@persian-tools/persian-tools";

digitsEnToFa("Card 1234"); // "Card ۱۲۳۴"
digitsEnToFa(2025); // "۲۰۲۵"
digitsFaToEn("شماره ۰۹۱۲"); // "شماره 0912"
digitsArToFa("٧٨٩"); // "۷۸۹"

// When input may have BOTH Persian and Arabic digits — most real user input
autoConvertDigitsToEN("تماس ۰۹۱۲ یا ٠٩١٣"); // "تماس 0912 یا 0913"

autoConvertDigitsToEN is the right default when ingesting unknown user input (form field, copy-paste, OCR).

Input rules and errors

digitsEnToFa / digitsEnToAr accept string | number. Anything else throws TypeError("PersianTools: digitsEnToFa - The input must be string or number") (and similarly for digitsEnToAr).
digitsFaToEn, digitsFaToAr, digitsArToEn, digitsArToFa accept string. Anything else throws TypeError("PersianTools: <fn> - The input must be string").
autoConvertDigitsToEN passes falsy input through as-is (no throw).

Exported constants

import { enNums, faNums, arNums, enDigitsRegex, faDigitsRegex, arDigitsRegex } from "@persian-tools/persian-tools";

enNums; // ["0", "1", ..., "9"]
faNums; // ["۰", "۱", ..., "۹"]
arNums; // ["٠", "١", ..., "٩"]

enDigitsRegex; // /[0-9]/g
faDigitsRegex; // /[۰۱۲۳۴۵۶۷۸۹]/g
arDigitsRegex; // /[٠١٢٣٤٥٦٧٨٩]/g

Use these when building larger custom regexes — don’t re-declare the character classes inline.

Types

import type { DigitsConverter } from "@persian-tools/persian-tools";

type DigitsConverter<I = string, O = string> = (value: I) => O;

Pitfalls

The strict converters throw on null / undefined / wrong types — they do NOT gracefully return "". Wrap in try/catch or guard upstream.
digitsFaToEn leaves Arabic digits untouched. Use autoConvertDigitsToEN for mixed input.
Hand-rolling with String.fromCharCode math is fragile — the Persian and Arabic ranges sit at different offsets. Use these functions.

Source

src/modules/digits/ (converters/, digits.constants.ts) · Tests: test/digits.spec.ts

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Digit Conversion

The three systems

Converters

Input rules and errors

Exported constants

Types

Pitfalls

Source

​The three systems

​Converters

​Input rules and errors

​Exported constants

​Types

​Pitfalls

​Source

The three systems

Converters

Input rules and errors

Exported constants

Types

Pitfalls

Source