tsconfig.es.json

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "target": "es2018",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
    "module": "es2015",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
    "lib": [ "dom" ],                             /* Specify library files to be included in the compilation. */
    "declaration": false,                   /* Generates corresponding '.d.ts' file. */
    "outDir": "./tmp/es",                        /* Redirect output structure to the directory. */
    "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
  },
  "files": [
    "src/index.ts"
  ],
  "exclude": [
    "src/**/*.spec.ts"
  ]
}