tsconfig.json

{
    "include": [
        "src",
        "test"
    ],
    "compilerOptions": {
        "lib": [
            "dom",
            "es2017"
        ],
        /* Basic Options */
        "target": "ES2015", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
        "module": "commonjs", /* Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'. */
        "sourceMap": true, /* Generates corresponding '.map' file. */
        "outDir": "./lib", /* Redirect output structure to the directory. */
        "rootDir": "./src", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
        "moduleResolution": "node", /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
        "strict": true,
        "noUnusedLocals": true
    }
}