tsconfig.json

{
  "compilerOptions": {
    "declaration": true, // emit declerations
    "declarationDir": ".", // to this dir
    "outDir": "./jsSrc", // but all other code to this dir
    "sourceMap": true, // allow sourcemap support
    "strictNullChecks": true, // enable strict null checks as a best practice
    // "module": "es6", // specify module code generation
    "jsx": "react", // use typescript to transpile jsx to js
    "allowJs": true, // allow a partial TypeScript and JavaScript codebase
    "allowSyntheticDefaultImports": true,
    // Include typings from built-in lib declarations
    "lib": ["es6", "es2019", "dom"],
    "target": "esnext",
    "skipLibCheck": true
  },
  "include": ["*/**/*.ts", "*/**/*.tsx"],
  "exclude": ["node_modules", "dist"]
}