SocialBlade/socialblade-js ? reverse-engineered prompt

Build me a small TypeScript library for Social Blade’s official API.

I want to be able to create a client with a client ID and access token, then call things like client.youtube.user('socialblade') and get back typed data for YouTube users. Please make it work nicely in both TypeScript and plain JavaScript, and keep the public API simple and friendly.

It should include the basic setup, a few example usages, and tests for the main methods. If the runtime needs fetch, mention that older Node versions may need a polyfill, but don’t force one in the library. Use the official Social Blade API docs if you need to check any request details or response shapes.

Please make the package feel polished, with good types, clear error handling, and a clean README example so someone can install it and use it right away.