Malaysian Postcode Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching malaysian postcode, 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

// Malaysian Postcode
// ReDoS-safe | RegexVault — Localization > Postal Codes

const malaysianPostcodeRegex = /^[0-9]{5}$/;

function validateMalaysianPostcode(input: string): boolean {
  return malaysianPostcodeRegex.test(input);
}

// Example
console.log(validateMalaysianPostcode("50000")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Postal Codes 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

Malaysian postcode ranges by state: Perlis 01000-02800, Kedah 05000-09810, Kuala Lumpur 50000-60000, Sabah 88000-91300, Sarawak 93000-98859. Pos Malaysia manages the database.