tsconfig.json

{
  "compilerOptions": {
    "target": "es2017" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */,
    "module": "commonjs" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
    "declaration": true /* Generates corresponding '.d.ts' file. */,
    "sourceMap": true /* Generates corresponding '.map' file. */, // "outFile": "./",                       /* Concatenate and emit output to single file. */
    "outDir": "dist/cjs" /* Redirect output structure to the directory. */,
    "strict": true /* Enable all strict type-checking options. */,
    "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */,
    "moduleResolution": "node",
    "resolveJsonModule": true
  },
  "include": ["./src"]
}