We use [TypeDoc](https://typedoc.org/) to generate documentation from all of our TypeScript. It combines type definitions with surrounding comment blocks for easily navigable, clean documentation.

For non-TypeScript codebases, we use [Docusaurus](https://docusaurus.io/).

I believe there are also plugins which can make TypeDoc output compatible with Docusaurus.

None of our docs are public at the moment, but a good example of documentation generated by TypeDoc would be Amazon's `aws-sdk`: https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/index...