tsconfig.json

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "moduleResolution": "node",
    "allowSyntheticDefaultImports": true,
    "allowJs": true,
    "importHelpers": true,
    "jsx": "react",
    "alwaysStrict": true,
    "sourceMap": true,
    "forceConsistentCasingInFileNames": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitReturns": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitAny": false,
    "noImplicitThis": false,
    "strictNullChecks": false,
    "lib": [
      "es5",
      "scripthost",
      "es2017",
      "dom",
      "esnext.asynciterable",
      "es2015.promise"
    ]
  },
  "include": [
    "src/**/*",
    "__tests__/**/*"
  ]
}