rxjs/Subject.d.ts error : Class 'Subject' incorrectly extends base class 'Observable'

Question

I extracted sample template code from this tutorial and did below two steps to get started -

1. npm install // worked fine and created node_modules folder

Answer 1

Using the above alone did not help, however, using the following approach: How do I get around this “Subject incorrectly extends Observable” error in TypeScript 2.4 and RxJs 5

solved the issues. It is also mentioned there that the issue has been fixed in RxJs 6, so this is more of a temporary fix, which helped me in successfully running this great example (which compiled before but gave the error during load time): Angular 4 application development with Bootstrap 4 and TypeScript