tsconfig.json

{
  "compilerOptions": {
    "target": "ES6",
    "useDefineForClassFields": true,
    "lib": ["DOM", "DOM.Iterable", "ESNext"],
    "module": "ESNext",
    "skipLibCheck": true,
    "typeRoots": ["./src/types"],

    /* bundler */
    "moduleResolution": "Node",
    "allowImportingTsExtensions": true,
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noEmit": true,
    "jsx": "react-jsx",

    /* linting */
    // Strict mode (9)
    "strict": true,
    "alwaysStrict": true,
    "noImplicitAny": true,
    "noImplicitThis": true,
    "strictNullChecks": true,
    "strictBindCallApply": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true,
    "useUnknownInCatchVariables": true,

    // No unused code (4)
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "allowUnusedLabels": false,
    "allowUnreachableCode": false,

    // No implicit code (2)
    "noImplicitOverride": true,
    "noImplicitReturns": true,

    // Others (5)
    "noUncheckedIndexedAccess": true,
    "noPropertyAccessFromIndexSignature": true,
    "noFallthroughCasesInSwitch": true,
    "exactOptionalPropertyTypes": true,
    "forceConsistentCasingInFileNames": true,
    /* linting - end */

    "esModuleInterop": false,
    "allowSyntheticDefaultImports": true
  },
  "include": ["src"]
}