tsconfig.json

{
  "compilerOptions": {
    /* Basic Options */
    "target": "es6" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */,
    "module": "es2015" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
    "lib": ["es6", "esnext", "dom"],
    "strict": true /* Enable all strict type-checking options. */,
    "outDir": "./build",
    "removeComments": true,
    "declaration": true,
    "strictNullChecks": false,
    "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
  },
  "include": ["./src/*.ts"]
}