docs(readme): document unsupported TS compiler options

[joelmukuthu]

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Tests

• Run the tests tests with npm test or yarn test not necessary, I think.

[kaisermann]

Just came to my mind that we can, apart from documenting, override them in the typescript transformer: https://github.com/kaisermann/svelte-preprocess/blob/master/src/transformers/typescript.ts#L198.

What do you think?

[joelmukuthu]

Hmm, I think that might cause some confusion. I think a better option is maybe to warn the user if they try to use unsupported options. I can work on that too but probably won't be till next weekend.

I'd also like to add a little more info to the README as to why they're not supported, but frankly I'm a bit confused myself. I have this setup:

• noUnusedLocals: true in tsconfig.json
• typescript: { tsconfigFile: './tsconfig.json' } in svelte-preprocess's options
• an unused local variable in a script lang="typescript" tag in a Svelte component

Building the project via webpack works while running tests on Jest (with ts-jest transforming TS to JS) fails with a ParseError: Unexpected character '�' error thrown by the svelte compiler. Does svelte-preprocess already ignore/bypass the TS compilation errors?

[kaisermann]

svelte-preprocess ignores only some import related diagnostics. Can you provide a minimal repro project?

[joelmukuthu]

@kaisermann you're right. I have a setup where a lot was going on and I couldn't reproduce it in a smaller project. Thank you for your time!