tsconfig.json

{
  "compileOnSave": true,
  "compilerOptions": {
    "allowJs": false,
    "allowUnreachableCode": false,
    "allowUnusedLabels": false,
    "baseUrl": ".",
    "paths": {
      "@/*": ["functions/*"]
    },
    "declaration": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "importHelpers": false,
    "module": "commonjs",
    "declarationMap": true,
    // "declarationDir": "types",
    "noEmitOnError": false,
    "noFallthroughCasesInSwitch": true,
    "noImplicitAny": false,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "outDir": "dist",
    "pretty": true,
    "removeComments": true,
    "stripInternal": true,
    "skipDefaultLibCheck": true,
    "skipLibCheck": true,
    "target": "es2017",
    "alwaysStrict": true,
    "lib": ["es2015", "es6"]
  },
  "include": ["functions/**/*", "types/**/*"],
  "exclude": ["tests"]
}