tsconfig.json

{
  "compilerOptions": {
    "rootDir": "./",
    "outDir": "./dist",
    "module": "commonjs",
    "target": "es2018",
    "moduleResolution": "node",
    "jsx": "react-jsx",
    "experimentalDecorators": true,
    "sourceMap": true,
    "strict": true,
    "allowJs": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitReturns": true,
    "noEmitOnError": true,
    "lib": ["dom", "esnext", "dom.iterable"],
    "allowSyntheticDefaultImports": true,
    "resolveJsonModule": true,
    "baseUrl": "src",
    "paths": {
      "testUtil": ["./utils/testUtil"]
    }
  },
  "files": ["custom.d.ts"],
  "include": ["src/**/*"],
  "exclude": [
    "node_modules",
    "src/**/*.(test|spec).ts*",
    "src/**/*.stories.ts*"
  ],
  "awesomeTypescriptLoaderOptions": {
    "errorsAsWarnings": true
  }
}