tsconfig.json

{
  "compilerOptions": {
    "target": "es2016" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
    "experimentalDecorators": true /* Enable experimental support for TC39 stage 2 draft decorators. */,
    "emitDecoratorMetadata": true /* Emit design-type metadata for decorated declarations in source files. */,
    "module": "commonjs" /* Specify what module code is generated. */,
    "outDir": "./build" /* Specify the output folder for all emitted files. */,
    "rootDir": "./src" /* Specify the root folder within your source files. */,
    "esModuleInterop": true /* Emit additional JavaScript to ease support for importing CommonJS modules. */,
    "forceConsistentCasingInFileNames": true /* Ensure that casing is correct in imports. */,
    "strict": true /* Enable all strict type-checking options. */,
    "strictPropertyInitialization": false /* Check for class properties that are declared but not set in the constructor. */,
    "skipLibCheck": true /* Skip type checking all .d.ts files. */
  }
}