tsconfig.json

{
  "include": ["src"],
  "compilerOptions": {
    "target": "es5",
    "module": "esnext",
    "lib": ["es2015", "dom", "es2016.array.include", "es2017.object"],
    "importHelpers": true,
    "declaration": true,
    "inlineSourceMap": true,
    "rootDir": "./src",
    "strict": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true,
    "noImplicitThis": true,
    "alwaysStrict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "moduleResolution": "node",
    "jsx": "react",
    "esModuleInterop": true,
    "outDir": "./lib",
    "skipLibCheck": true,
    "declarationMap": true,
    "downlevelIteration": true,
    "allowSyntheticDefaultImports": true
  }
}