What's the best practice for securing API keys in a JavaScript application?
API keys should never be exposed in client-side JavaScript code as they can be easily extracted. The best practice is to: 1) Keep sensitive keys server-side only, 2) Use environment variables for server configuration, 3) Implement proper authentication for client-server communication, 4) Use proxy endpoints for API calls requiring keys. Remember that anything in client-side code is accessible to users.