tsconfig.json

{
  "compilerOptions": {
    "alwaysStrict": true,
    "target": "es2017",
    "module": "es2015",
    "moduleResolution": "node",
    "lib": ["esnext.array", "esnext", "es2017", "dom"],
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true,
    "inlineSources": true,
    "strict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitAny": true,
    "noImplicitThis": true,
    // Only necessary because @types/uglify-js can't find types for source-map
    "skipLibCheck": true,
    "experimentalDecorators": true,
    "allowSyntheticDefaultImports": true,
    "allowUnreachableCode": false,
    "forceConsistentCasingInFileNames": true,
    "jsx": "react",
    "jsxFactory": "h",
    "emitDecoratorMetadata": true,
    "strictNullChecks": true,
    "noEmitOnError": true
  }
}