Provide TypeScript declarations out-of-the-box

[benmccann]

Right now people have to copy the below file into their project. We should generate it automatically:

https://github.com/babichjacob/sapper-typescript-graphql-template/blob/main/types/%40sapper/index.d.ts

[babichjacob]

Is it the right idea to make this only be done after running a Sapper-oriented fork of scripts/setupTypeScript.js that gets bundled with the default Rollup and Webpack templates?

[benmccann]

I was thinking that it could live in something like create_app and always happen. People don't generally open up their src/node_modules/@sapper directory, so it will be hidden from them and not affect them if they're not using TypeScript. And it requires no user action for the people that do use TypeScript

[benmccann]

I sent #1402 to provide TypeScript declarations automatically

We did get a request to add a scripts/setupTypeScript.js to sapper-template. That might not be a bad idea to do as a next step if anyone wants to take a stab at it

[martonlederer]

I might take a look at it and see if I can do it @benmccann