JavaScript Security Best Practices

const url = `https://api.example.com/user/${userId}`;

URL encoding issues
Path traversal
Parameter pollution
All of the above
This code could introduce multiple vulnerabilities: 1) URL encoding issues if userId contains special characters, 2) Path traversal if userId contains '../' sequences, 3) Parameter pollution if userId contains query strings. To prevent these, always encode parameters properly using encodeURIComponent() and validate input to ensure it matches expected formats.