tsconfig.json

{
    "include": [
        "./src"
    ],
    "compilerOptions": {
        "outDir": "./built", /* Redirect output structure to the directory. */
        "rootDir": "./src", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
        "skipLibCheck": true,
        /* Basic Options */
        "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'. */
        "lib": [
            "es2017"
        ],
        "declaration": true, /* Generates corresponding '.d.ts' file. */
        "declarationMap": true, /* Generates a sourcemap for each corresponding '.d.ts' file. */
        "sourceMap": true, /* Generates corresponding '.map' file. */
        "composite": true, /* Enable project compilation */
        /* Strict Type-Checking Options */
        "strict": true, /* Enable all strict type-checking options. */
        "strictNullChecks": false, /* Enable strict null checks. */
        /* Module Resolution Options */
        "moduleResolution": "node", /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
        "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    }
}