tsconfig.json

{
  "compilerOptions": {
    "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": ["es2015", "es2016"],                        /* Specify library files to be included in the compilation. */
    "outDir": "./built/",                     /* Redirect output structure to the directory. */
    "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. */
    "noImplicitAny": true,                    /* Raise error on expressions and declarations with an implied 'any' type. */
    "strictNullChecks": true,                 /* Enable strict null checks. */
    "strictFunctionTypes": true,              /* Enable strict checking of function types. */
    "strictPropertyInitialization": true,     /* Enable strict checking of property initialization in classes. */
    "noImplicitThis": true,                   /* Raise error on 'this' expressions with an implied 'any' type. */
    "noUnusedLocals": true,                   /* Report errors on unused locals. */
    "noUnusedParameters": true,               /* Report errors on unused parameters. */
    "esModuleInterop": true,                  /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. */
    "resolveJsonModule": true,
    "plugins": [
      { "name": "tslint-language-service" }
    ]
  }
}