tsconfig.json

{
  "compilerOptions": {

    /* Configuration options. */

    // What to emit in.
    "target": "es2018",

    // What polyfills to include.
    // "esnext" includes the latest everything. "dom" includes stuff used by things like @reduxjs/toolkit typings.
    "lib": ["dom", "esnext"],


    /* Modules options. */

    // The module structure to use.
    "module": "commonjs",

    // Already the default.
    // "moduleResolution": "node",

    // Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports.
    // Implies 'allowSyntheticDefaultImports'.
    "esModuleInterop": true,


    /* Build & emit options. */

    "outDir": "build",
    "declaration": true,
    // "sourceMap": true,


    /* Strictness options. */

    "strict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitOverride": true,
    "noPropertyAccessFromIndexSignature": true,
    "noUncheckedIndexedAccess": true

  },
  "include": ["src"],
  "exclude": ["src/*.test.ts"]
}