node_modules/rxjs/src/tsconfig.cjs.json

{
  "extends": "./tsconfig.base.json",
  "compilerOptions": {
    "module": "commonjs",
    "target": "es5",
    "downlevelIteration": true,
    "outDir": "../dist/cjs"
  },
  "exclude": ["./internal/umd.ts"]
}