You mean Lightsail? Straight from the website, all Lightsail plans include
Static IP address
Intuitive management console
DNS management
1-click SSH terminal access (Linux/Unix)
1-click RDP access (Windows)
Powerful API
Highly available SSD storage
Server monitoring
But, you don’t actually need that plan if all you are serving is “client-side JavaScript”. You can try the AWS Amplify Console; look here: Web Hosting - Amazon Web Services (AWS)
The Storage Service has its own console to, for example, upload and download files by dragging them to or from a browser window.
You can configure all of these services from the AWS Management Console. Anyway, the point is that you can sign up for a free trial of all these services, so you know exactly what you will be getting.