Some exercises don't have answers, clicking "Show all answers" clears the code

[krivulcik]

Some exercises which are actually demonstrations don't have answers in the code. This causes them to lose the demonstration code when the user clicks the "Show all the answers so I can just browse." button.

Exercises affected:

• Exercise 28: Subscribing to an event
• Exercise 29: Traversing an Event
• Exercise 34: HTTP requests
• Exercise 35: Sequencing HTTP requests with callbacks
• Exercise 36: Traversing callback-based Asynchronous APIs
• Exercise 37: Sequencing HTTP requests with Observable

[IgnacioCorto]

This tutorial is used as a lesson in Free Code Camp, so it seems uncomfortable to mark that step as completed when 6 of 42 exercises can't understood. Are these answers in the source code?