tsconfig.json

{
  "compilerOptions": {
    /* Basic Options */
    "target": "esnext",
    "module": "esnext",
    "moduleResolution": "node",
    "lib": ["esnext.array", "esnext", "dom"],
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true,
    // "inlineSources": true,
    /* Strict Type-Checking Options */
    "strict": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true,
    "alwaysStrict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": false,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitAny": true,
    "noImplicitThis": true,
    //
    "forceConsistentCasingInFileNames": true,
    //
    "rootDir": "./src",
    "outDir": "./build",
    /* Module Options */
    "esModuleInterop": true,
    "allowJs": true,
    "checkJs": true,
    // Only necessary because @types/uglify-js can't find types for source-map
    // "skipLibCheck": true,
    "experimentalDecorators": true,
    "useDefineForClassFields": true
  },
  "include": ["./src"]
}