tsconfig.json

{
  "compilerOptions": {
    /* Basic Options */
    "target": "ES2019" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */,
    "module": "ES2020" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
    "lib": [
      /* Specify library files to be included in the compilation. https://github.com/microsoft/TypeScript/tree/master/lib */
      "ESNext",
      "DOM",
      "DOM.Iterable"
    ],
    "declaration": true /* Generates corresponding '.d.ts' file. */,
    "sourceMap": true /* Generates corresponding '.map' file. */,
    "declarationMap": false /* Generates a sourcemap for each corresponding '.d.ts' file. */,
    // "outDir": "./",                        /* Redirect output structure to the directory. */
    "rootDir": "./src" /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */,
    // "composite": true,                        /* Enable project compilation */
    // "incremental": true,                   /* Enable incremental compilation */
    // "tsBuildInfoFile": ".tsbuildinfo",     /* Specify file to store incremental compilation information */
    "removeComments": true /* Do not emit comments to output. */,
    "importHelpers": true /* Import emit helpers from 'tslib'. */,
    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */

    /* Strict Type-Checking Options */
    "strict": true /* Enable all strict type-checking options. */,
    // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
    // "strictNullChecks": true,              /* Enable strict null checks. */
    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
    // "strictBindCallApply": true,           /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
    // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
    "noImplicitThis": true /* Raise error on 'this' expressions with an implied 'any' type. */,
    "alwaysStrict": true /* Parse in strict mode and emit "use strict" for each source file. */,

    /* Additional Checks */
    "noUnusedLocals": true /* Report errors on unused locals. */,
    "noUnusedParameters": true /* Report errors on unused parameters. */,
    "noImplicitReturns": true /* Report error when not all code paths in function return a value. */,
    "noFallthroughCasesInSwitch": true /* Report errors for fallthrough cases in switch statement. */,
    "noImplicitOverride": true /* Force to use override keyword when override super class methods. */,

    /* Module Resolution Options */
    "moduleResolution": "node" /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */,
    // "esModuleInterop": true,               /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    "allowSyntheticDefaultImports": true /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */,
    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
    // "baseUrl": "./package",                /* Base directory to resolve non-absolute module names. */

    /* Experimental Options */
    "skipLibCheck": true /* Skip type checking of declaration files. Requires TypeScript version 2.0 or later. */,
    "experimentalDecorators": true /* Enables experimental support for ES7 decorators. */,
    // "emitDecoratorMetadata": false,        /* Enables experimental support for emitting type metadata for decorators. */
    "forceConsistentCasingInFileNames": true /* Follows the case sensitivity rules of the file system it’s running on. */,
    "useDefineForClassFields": false /* Must be disabled for lit, https://lit.dev/docs/components/properties/#avoiding-issues-with-class-fields */,

    "plugins": [
      {
        "name": "ts-lit-plugin",
        "rules": {
          // error
          "no-unknown-tag-name": "error",
          "no-unclosed-tag": "error",
          "no-unknown-property": "error",
          "no-unintended-mixed-binding": "error",
          "no-invalid-boolean-binding": "error",
          "no-expressionless-property-binding": "error",
          "no-noncallable-event-binding": "error",
          "no-boolean-in-attribute-binding": "error",
          "no-complex-attribute-binding": "error",
          "no-nullable-attribute-binding": "error",
          "no-incompatible-type-binding": "error",
          "no-invalid-directive-binding": "error",
          "no-incompatible-property-type": "error",
          "no-unknown-property-converter": "error",
          "no-invalid-attribute-name": "error",
          "no-invalid-tag-name": "error",
          "no-property-visibility-mismatch": "error",
          // off
          "no-unknown-attribute": "off",
          "no-unknown-event": "off",
          "no-unknown-slot": "off",
          "no-invalid-css": "off"
        }
      }
    ]
  },

  "include": ["src/**/*.ts"] /* Specifies a list of glob patterns that match files to be included in compilation. */,
  "exclude": [] /* Specifies a list of files to be excluded from compilation. */
}