Combining all three `tsconfig.json` files results in build error for `ui` package

[brandonpittman]

Thanks for this example!

I'm trying to just build a library as a standalone package. I combined all the extended tsconfig files with the one in the ui package like this:

{
  "compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "tsBuildInfoFile": "./tsconfig.tsbuildinfo",
    "declarationDir": "dist",
    "composite": false,
    "declaration": true,
    "declarationMap": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "incremental": true,
    "inlineSources": false,
    "isolatedModules": true,
    "moduleResolution": "node",
    "noEmit": true,
    "noUnusedLocals": false,
    "noUnusedParameters": false,
    "preserveWatchOutput": true,
    "resolveJsonModule": true,
    "skipLibCheck": true,
    "strict": true,
    "lib": ["dom", "dom.iterable", "esnext"],
    "module": "ESNext",
    "target": "ES6",
    "jsx": "preserve"
  },
  "exclude": ["node_modules"],
  "include": ["src"]
}

When they're split up and extended in your example, the build succeeds, but when combining them into one file, this error occurs:

src/index.ts → dist...
[!] (plugin dts) Error: Syntax not yet supported

> 1 | {"version":3,"file":"index.d.ts","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":"AAAA,cAAc,cAAc,CAAC;AAC7B,cAAc,UAAU,CAAC;AACzB,cAAc,UAAU,CAAC;AACzB,cAAc,SAAS,CAAC;AACxB,cAAc,eAAe,CAAC"}

Any idea why this might be?