tsconfig.json

{
  "compilerOptions": {
    // Target latest version of ECMAScript.
    "target": "esnext",
    // Search under node_modules for non-relative imports.
    "moduleResolution": "node",
    // Process & infer types from .js files.
    "allowJs": true,
    // Enable strictest settings like strictNullChecks & noImplicitAny.
    "strict": true,
    // Import non-ES modules as default imports.
    "esModuleInterop": true,
    "noImplicitAny": false,
    // Ensure that .d.ts files are created by tsc, but not .js files
    "declaration": true,
    "emitDeclarationOnly": true,
    // Ensure that Babel can safely transpile files in the TypeScript project
    "isolatedModules": true,
    "outDir": "lib",
  }, 
  "include": [
    "src"
  ]
}