tsconfig.json

{
    "compilerOptions": {
        "target": "ES2018",                          /* 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"],                             /* Specify library files to be included in the compilation. */
        "declaration": true,                   /* Generates corresponding '.d.ts' file. */
        "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
        "outDir": "./dist",                        /* Redirect output structure to the directory. */
        "rootDir": "./src",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
        "composite": true,                     /* Enable project compilation */
        "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
        "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'. */
        "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
        "emitDecoratorMetadata": true
    }
}