GitHub Actions Workflow Expression Regex for JavaScript

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching github actions workflow expression, 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

// GitHub Actions Workflow Expression
// ReDoS-safe | RegexVault — Dev & Systems > Git

const githubActionsWorkflowExpressionRegex = /^\$\{\{\s+(?:github|env|vars|secrets|inputs|runner|job|steps|needs|matrix|strategy)(?:\.[a-zA-Z_][a-zA-Z0-9_\-]*)+\s+\}\}$/;

function validateGithubActionsWorkflowExpression(input: string): boolean {
  return githubActionsWorkflowExpressionRegex.test(input);
}

// Example
console.log(validateGithubActionsWorkflowExpression("${{ github.sha }}")); // 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

Requires at least two dot-separated components (context.property). Context names are lowercase in GitHub Actions. The i flag is not needed.