Git Commit Hash (Full SHA-1) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching git commit hash (full sha-1), 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 Commit Hash (Full SHA-1)
// ReDoS-safe | RegexVault — Dev & Systems > Git

const gitCommitHashFullSha1Regex = /^[0-9a-fA-F]{40}$/;

function validateGitCommitHashFullSha1(input: string): boolean {
  return gitCommitHashFullSha1Regex.test(input);
}

// Example
console.log(validateGitCommitHashFullSha1("a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0")); // 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

Git is transitioning from SHA-1 to SHA-256. SHA-256 hashes are 64 hex chars (dev-git-02). The all-zeros hash represents the null tree object.