A New-Year special exercise

In the first episode we created a stream from user clicks. Let’s see a new way of creating streams.

A clock is another source of events. Tick, tock. With ❚ interval you can create a stream that emits incremental numbers, periodically. For example, with a period of 1000 milliseconds, it will work like this:

  • 1000ms after the stream has started, it emits 0
  • Then, after 1000ms, it emits 1
  • And so on

Note: this is how it works in RxJS. It may be a bit different with some other reactive libraries. I will compare them in a future episode.

New-Year exercise 🎉

Now, are you ready for a little challenge?

  • Create a countdown from 10 to 0
    • The stream starts immediately with 10
    • The stream completes immediately after 0

Begin with Rx.Observable.interval(1000) (or the equivalent in the reactive library you use) and complete with some operators we have seen in the previous episodes. You can see an overview of the different stream operations we have learned about so far on reactive.how/categories.

I’ve set up a ready-to-use sandbox so you can easily write and test your solution. You can reply to this email if you need help or want a review of your solution 😉.

Write and test your solution in the sandbox »

Cédric Soulas Follow Hire me

Freelance Developer Advocate. Motion graphics with code. JavaScript and Elm. cedricsoulas.com

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