Chinese Postal Code Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching chinese postal code, 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

// Chinese Postal Code
// ReDoS-safe | RegexVault — Localization > Postal Codes

const chinesePostalCodeRegex = /^[1-9][0-9]{5}$/;

function validateChinesePostalCode(input: string): boolean {
  return chinesePostalCodeRegex.test(input);
}

// Example
console.log(validateChinesePostalCode("100000")); // 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

Chinese postal codes: first two digits represent province (10=Beijing, 20=Shanghai, 21=Liaoning, 31=Shanghai municipality, 44=Guangdong, 61=Shaanxi). China Post manages the assignment. Hong Kong and Macau do not use postal codes.