Example request

> It will be good if you could provide us an example for abstract class and properties here.

Made here https://www.gitbook.com/book/basarat/typescript/discussions/64

Start with the TypeScript book section related to abstract classes and properties, and review the linked GitBook discussion at discussion/64 for context. Add a clear example covering both requested concepts in the relevant documentation, then verify that the example appears correctly in the book.

Written by the indexing model from the issue text.