Unicode Script Code (ISO 15924) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching unicode script code (iso 15924), ported and verified for JavaScript. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// Unicode Script Code (ISO 15924)
// ReDoS-safe | RegexVault — Localization > Locale & Language

const unicodeScriptCodeIso15924Regex = /^[A-Z][a-z]{3}$/;

function validateUnicodeScriptCodeIso15924(input: string): boolean {
  return unicodeScriptCodeIso15924Regex.test(input);
}

// Example
console.log(validateUnicodeScriptCodeIso15924("Latn")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Locale & Language category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

ISO 15924 script codes: Latn=Latin, Hans=Simplified Chinese, Hant=Traditional Chinese, Arab=Arabic, Cyrl=Cyrillic, Deva=Devanagari (Hindi), Hang=Hangul, Jpan=Japanese (Han+Hiragana+Katakana). Used in BCP 47 language tags.