tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es6",
    "outDir": "output",
    "sourceMap": false,
    "experimentalDecorators": true,
    "allowJs": true,
    "moduleResolution": "node",
    "baseUrl": ".",
    "paths": {
      "*": [ "./node_modules/@types/*" ]
    }
  },
  "include": [ "./functions/**/*.ts" ]
}