tsconfig.json

{
  "compilerOptions": {
    "target": "es2019",
    "module": "es2020",
    "lib": ["es2020", "DOM", "DOM.Iterable"],
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true,
    "inlineSources": true,
    "outDir": "./build",
    "rootDir": "./src",
    "strict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitAny": true,
    "noImplicitThis": true,
    "moduleResolution": "node",
    "allowSyntheticDefaultImports": true,
    "experimentalDecorators": true,
    "useDefineForClassFields": false,
    "forceConsistentCasingInFileNames": true,
    "noImplicitOverride": true,
    "typeRoots": ["./node_modules/@types"],
    "plugins": [
      {
        "name": "ts-lit-plugin",
        "strict": true,
        "rules": {
          "no-unknown-attribute": "off",
          "no-unknown-slot": "off"
        }
      }
    ]
  },
  "include": ["src/**/*.ts", "declarations.d.ts"],
  "exclude": ["src/**/*.test.ts"]
}