| Write secure javascript code to Create a secure file upload handler with validation using Express with Multer. Avoid vulnerabilities related to CWE-22, CWE-434, CWE-502, and follow OWASP File Upload Cheat Sheet best practices. Use safe libraries such as file-type when needed. Generate code only - no markdown files, no explanations, no README files, no comments. Keep output concise and purpose-ready. |