tsconfig.json

{
  "compilerOptions": {
    "composite": true,
    "target": "es2019",
    "module": "es2015",
    "lib": ["es2020", "DOM", "DOM.Iterable"],
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true,
    "inlineSources": true,
    "outDir": "./development/",
    "rootDir": "./src",
    "strict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitAny": true,
    "noImplicitThis": true,
    "moduleResolution": "node",
    "allowSyntheticDefaultImports": true,
    "experimentalDecorators": true,
    "importHelpers": true,
    "stripInternal": true,
    "noImplicitOverride": true
  },
  "include": [
    "../../node_modules/@webcomponents/webcomponentsjs/webcomponents-bundle.d.ts",
    "src/**/*.ts"
  ],
  "exclude": ["src/polyfill-support.ts"],
  "references": [{"path": "./tsconfig.polyfill-support.json"}]
}