tsconfig.json

{
  "compilerOptions": {
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ],
    /* Language and Environment */
    "target": "es2016",
    "jsx": "react-jsx",

    /* Modules */
    "moduleResolution": "node",
    "module": "esnext",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "baseUrl": "src",
    "allowSyntheticDefaultImports": true,

    /* JavaScript Support */
    "allowJs": false,

    /* Emit */
    "noEmit": true,
    "outDir": "build",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,

    /* Type Checking */
    "strict": true,
    "alwaysStrict": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictBindCallApply": true,
    "strictPropertyInitialization": true,
    "noImplicitThis": true,
    "noUncheckedIndexedAccess": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": false,
    "noFallthroughCasesInSwitch": true,
    "noImplicitOverride": true,
    "allowUnusedLabels": true,
    "allowUnreachableCode": false,

    /* Completeness */
    "skipDefaultLibCheck": true,
    "skipLibCheck": true
  },
  "include": [
    "src"
  ]
}