Fiscal Quarter (QN YYYY or YYYY QN) Regex for JavaScript

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching fiscal quarter (qn yyyy or yyyy qn), 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

// Fiscal Quarter (QN YYYY or YYYY QN)
// ReDoS-safe | RegexVault — Localization > Date Formats

const fiscalQuarterQnYyyyOrYyyyQnRegex = /^(?:(Q[1-4])\s+((?:19|20)[0-9]{2})|((?:19|20)[0-9]{2})\s+(Q[1-4]))$/i;

function validateFiscalQuarterQnYyyyOrYyyyQn(input: string): boolean {
  return fiscalQuarterQnYyyyOrYyyyQnRegex.test(input);
}

// Example
console.log(validateFiscalQuarterQnYyyyOrYyyyQn("Q1 2024")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Date Formats 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

Capture groups: 1=quarter (QN format), 2=year (QN format), 3=year (YQ format), 4=quarter (YQ format). Fiscal quarters may not align with calendar quarters — Q1 may start in January, April, July, or October depending on the company's fiscal year.