tsconfig.json

{
  "compilerOptions": {
    /* Basic Options */
    "target": "ES5",
    /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
    "module": "commonjs",
    /* Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'. */
    "lib": [
      /* Specify library files to be included in the compilation:  */
      "esnext",
      /** USed in Jest tests */
      "dom"
    ],
    "sourceMap": true,
    /* Strict Type-Checking Options */
    "noImplicitThis": false,
    /* Raise error on 'this' expressions with an implied 'any' type. */
    "alwaysStrict": true,
    /* Additional Checks */
    "noUnusedLocals": true,
    /* Report errors on unused locals. */
    // "noUnusedParameters": true,            /* Report errors on unused parameters. */
    "noImplicitReturns": true,
    /* Report error when not all code paths in function return a value. */
    "noFallthroughCasesInSwitch": true,
    /* Module Resolution Options */
    "typeRoots": [
      "node_modules/@types",
      "src/typings"
    ],
    "outDir": "./build"
  },
  "exclude": [
    "node_modules",
    "**/*.spec.ts"
  ]
}