tsconfig.json

{
  "compilerOptions": {
    "target": "es5",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
    "module": "commonjs",                                /* Specify what module code is generated. */
    "lib": ["esnext"],
    "rootDir": "src",                                  /* Specify the root folder within your source files. */
    "moduleResolution": "node",                       /* Specify how TypeScript looks up a file from a given module specifier. */
    "baseUrl": ".",                                  /* Specify the base directory to resolve non-relative module names. */
    "declaration": true,                              /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
    "outDir": "lib",                                   /* Specify an output folder for all emitted files. */
    "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
    "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
    "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables `allowSyntheticDefaultImports` for type compatibility. */
    "strict": true,                                      /* Enable all strict type-checking options. */
    "noImplicitAny": true,                            /* Enable error reporting for expressions and declarations with an implied `any` type.. */
    "strictNullChecks": true,                         /* When type checking, take into account `null` and `undefined`. */
    "skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
  }
}