tsconfig.json

{
  "compilerOptions": {
    // Enables all strict type checking options.
    "strict": true,

    // Library files to be included in the compilation. Basically which "core
    // language features" TypeScript should enable.
    "lib": ["es2015", "es2016", "es2017"],

    // Which version of EcmaScript TypeScript should transpile to. Because of
    // how Babel and Webpack is set up we currently target `esnext`, and let
    // Babel take care of transpiling it down.
    "target": "esnext",

    // Specifies module code generation.
    "module": "esnext",

    // Allows default imports from modules with no default export. This does not affect code emit, just type checking.
    // We have to enable this option explicitly since `esModuleInterop` doesn't enable it automatically when ES2015 or
    // ESNext module format is used.
    "allowSyntheticDefaultImports": true,

    // Emits __importStar and __importDefault helpers for runtime babel ecosystem compatibility.
    "esModuleInterop": true,

    // Resolve modules in the same way as Node.js. Aka make `require` works the
    // same in TypeScript as it does in Node.js.
    "moduleResolution": "node",

    // Disallow inconsistently-cased references to the same file.
    "forceConsistentCasingInFileNames": true,

    // Generate an external source map. There's also an `--inlineSourceMap` for
    // emitting a single file with source maps instead of having a separate file.
    "sourceMap": true
  },

  "exclude": [
    "node_modules"
  ]
}