Git Abbreviated Commit Hash Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching git abbreviated commit hash, 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

// Git Abbreviated Commit Hash
// ReDoS-safe | RegexVault — Dev & Systems > Git

const gitAbbreviatedCommitHashRegex = /^[0-9a-fA-F]{4,40}$/;

function validateGitAbbreviatedCommitHash(input: string): boolean {
  return gitAbbreviatedCommitHashRegex.test(input);
}

// Example
console.log(validateGitAbbreviatedCommitHash("a1b2")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Git 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

GitHub and GitLab display 7-char abbreviated hashes by default. The minimum for guaranteed uniqueness varies by repository size. Always use full hashes in CI/CD artifact tagging.