tsconfig.json

{
  "compilerOptions": {
    "target": "es6",
    "alwaysStrict": true,
    "noImplicitAny": true,
    "noImplicitReturns": true,
    "noImplicitThis": true,
    "noEmitOnError": true,
    "strictNullChecks": true,
    "moduleResolution": "Node"
  }
}