Apollo server 2.0 - DatasourceREST - Improve types

[fabien0102]

Hello,

I'm just begining to play a little bit with Apollo server 2.0, datasourceRest and typescript.

This PR include some little improvements:

• Use generics instead of any to permit to type the response easily
• Use the full type from URLSearchParams to be more precise about the possibilities of the API
• Add PATCH method

[martijnwalraven]

Thanks, this looks great! The new Params typing won't work as is because we use Object.keys(params).length > 0 to check whether to append the params. I'll change this, and also extract a URLSearchParamsInit as part of the URL type definitions, so we don't have to duplicate typings.

[martijnwalraven]

I ended up defining URLSearchParamsInit to take Object as values instead of string because I wanted to allow implicit coercion from numbers and booleans. That at least seems to be defined behavior for Node, not entirely sure about the WHATWG standard.

I also added any as a default type parameter for TResponse, to keep the existing behavior and not force people to specify a result type.

[fabien0102]

@martijnwalraven Nice! Thank you for your support and your reactivity 💯