Writing preval files in TypeScript

[alexgleason]

When using // @preval at the top of the file, it's first evaluated in Node.js. This means that TypeScript has no idea what's going on. If I leave these files as vanilla JS (.js) it's okay (the import gets an any type in TS), but then we don't get the advantages of TypeScript.

Can I write preval files themselves in TypeScript? Maybe with ts-node?

[alexgleason]

@mpeyper since you converted this repo to TypeScript in #86... do you know if this is possible?

[mpeyper]

Sorry, I’m not sure.

It might be possible to support processing of preval snippets with ts, but I think having the resulting types pass through to other code trying to use the output would be quite difficult, if not impossible.

[pedromchd]

Hey, I'm trying to use preval with Expo/Typescript, but I can't get properly typing assertion and indexing, is there any solution to this?

// babel.config.js
module.exports = function (api) {
  api.cache(true);
  return {
    presets: [['babel-preset-expo', { jsxImportSource: 'nativewind' }], 'nativewind/babel'],
    plugins: ['babel-plugin-preval'],
  };
};

I created a d.ts file, but doesn't cover such things as preval.require:

// preval.d.ts
declare function preval(strings: TemplateStringsArray): any;