isArabic

Development

Detect whether a string is in the Arabic script or contains Arabic characters. Use when separating Arabic from Persian/Farsi input, validating that text is Arabic before applying Arabic-specific NLP, or routing multilingual input. Triggers on mentions of isArabic, hasArabic, Arabic detection, Arabic script validation, or "is this Arabic vs Persian".

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Source SKILL.md: https://github.com/persian-tools/persian-tools/blob/HEAD/skills/isArabic/SKILL.md

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isArabic — Arabic-script detection

import { isArabic, hasArabic } from "@persian-tools/persian-tools";
// CommonJS
const { isArabic, hasArabic } = require("@persian-tools/persian-tools");

Public exports

isArabic(str: string, trimPattern?: RegExp): boolean
hasArabic(str: string): boolean

isArabic vs hasArabic

isArabic(str) — all of str (after trimming) is Arabic-script.
hasArabic(str) — str contains at least one Arabic-script character.

isArabic("السلام عليكم");        // true
isArabic("Hello مرحبا");          // false
hasArabic("Hello مرحبا");         // true

How it works

The check is two-pronged (src/modules/isArabic/index.ts:11):

The string (post-trim) matches /^[؀-ۿ\s]+$/ — every character is in the Arabic Unicode block.
The string matches the project's ArabicContextualForms regex (src/helpers/contextual-forms.ts) — ensures actual Arabic letterforms are present (rules out e.g. pure punctuation in the Arabic block).

Both conditions must be true. hasArabic is the same logic but accepts any string that contains at least one qualifying character.

The `trimPattern` parameter

Default: /["'-+()\s.]/g — common Arabic punctuation, parentheses, dots, quotes, and whitespace are stripped before the script check.

Override when your input has additional separators:

isArabic("السلام / عليكم", /[/\s]/g);   // true

Persian vs Arabic — the critical distinction

The Persian alphabet is the Arabic script plus پ چ ژ گ and minus a few rarely-used Arabic letters. Many letters appear in both scripts at different code points:

Glyph	Persian	Arabic
ya (ی/ي)	U+06CC	U+064A
kaf (ک/ك)	U+06A9	U+0643

Practical implication:

A string typed on an Arabic keyboard contains ي and ك and passes isArabic while failing isPersian.
A string typed on a Persian keyboard contains ی and ک and passes isPersian while passing isArabic too (the Persian code points still fall in U+06xx).

So isPersian(x) && !isArabic(x) is not a clean partition. The two are not mutually exclusive. To detect "this is Arabic and not Persian":

import { isArabic, hasPersian } from "@persian-tools/persian-tools";

const isPureArabic = (s: string) => isArabic(s) && !hasPersian(s);
isPureArabic("السلام");        // true
isPureArabic("علی");           // false — contains Persian-specific ya

Common edge cases

Input	`isArabic(...)`
`""`	`false`
`"السلام"`	`true`
`"عليكم 123"`	`false` — Latin digits aren't in the Arabic block
`"عليكم ١٢٣"`	`true` — Arabic-Indic digits (٠-٩) ARE in the Arabic block
`"سلام"` (Persian)	also `true` — letters are in U+06xx; not a Persian-Arabic discriminator on its own

Common pitfalls

Don't use isArabic as the negation of isPersian — see "Persian vs Arabic" above.
Arabic-Indic digits (٠-٩) pass as Arabic, but Persian digits (۰-۹) do too because both ranges are in U+06xx. If you need digit-level distinction, use arDigitsRegex and faDigitsRegex from the digits module.
Empty/whitespace-only strings return false. Validate non-emptiness separately if needed.

References

Helper: src/helpers/contextual-forms.ts
Sibling: src/modules/isPersian/ (for Persian-specific detection)
Tests: test/isArabic.spec.ts
Domain background: .agents/persian-text-expert/SKILL.md