CRA does not check for presence of emitDeclarationOnly in tsconfig

Created by: squidsoup

Describe the bug

I maintain a react component library, written in TypeScript. Our components use sass, and consequently we build the library using babel rather than tsc, and use tsc for generating type declarations with emitDeclarationOnly: true.

We do want to continue using CRA, however every time we touch react-scripts it adds noEmit: true to our .tsconfig which is incompatible with emitDeclarationOnly. Please note that these two keywords are incompatible with each other, settings noEmit: false is not a solution, and this is overwritten by react-scripts to true at any rate.

This makes CRA largely unusable for maintaining a TypeScript component library unfortunately.

Originally posted as a discussion.

Did you try recovering your dependencies?

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Which terms did you search for in User Guide?

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Environment

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Steps to reproduce

Set emitDeclarationOnly: true in .tsconfig.
Run a yarn script that uses react-scripts e.g. yarn test

Expected behavior

noEmit should not be added if emitDeclarationOnly is present.

Actual behavior

noEmit: true is added to .tsconfig, breaking the build.

Reproducible demo

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