feat(compiler): support paths in compiler options

[simonhaenisch]

Someone was asking about why path aliases in the compilerOptions section of tsconfig didn't work in Stencil, and I ended up trying to solve it.

First, I created rollup-plugin-typescript-paths, which uses nodeModuleNameResolver from the typescript api to resolve imports using the path aliases (it returns the transpiled .js counterpart of the .ts file).

Then I realized that I had an issue with const enums: Stencil removes the paths field from the compiler options entirely (in transpile-service.ts), which causes the import statements of any const enums to remain in the file even though they have disappeared during transpilation (like interfaces).

To solve this I decided to implement the resolving of path aliases in Stencil itself, because it's relatively simple and the only reason I wrote my plugin was for use with Stencil (though it should theoretically work in other contexts).

To try it out:

• npm link in stencil
• npm init stencil app foobar
• cd foobar, npm link @stencil/core
• change files:

// tsconfig.json
{
  // ...
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@foobar": ["src/global/app"]
    }
  }
}

// src/global/app.ts

export const foobar = 'foobar';

// src/components/app-home/app-home.tsx

import { foobar } from '@foobar';

render() {
  return <div>{foobar}</div>;
}

BTW I tried writing a test but didn't have enough time to figure out how to change the compiler options within the test.

[leoafarias]

Just a bump on this.. spent a lot more that I care to admit trying to see if was an issue on my end or not.

[rainzhao2000]

Bump for sure, awesome of you to implement a solution!