tsconfig.json

{
  "compilerOptions": {
    "target": "es2019",
    "module": "esnext",
    "lib": [
      "esnext",
      "dom"
    ],
    "useDefineForClassFields": false,
    "sourceMap": true,
    "declaration": true,
    "outDir": "./dist/types",
    "rootDir": "./src",
    "removeComments": true,
    "strict": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictBindCallApply": true,
    "strictPropertyInitialization": true,
    "noImplicitThis": true,
    "alwaysStrict": true,
    "noUnusedLocals": false,
    "noUnusedParameters": false,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "moduleResolution": "node",
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "plugins": [
      {
        "name": "typescript-lit-html-plugin"
      }
    ]
  }
}