Chapter 1
Creating Observables

If you’re brand new to the concepts in observables or just need a refresher, this is the chapter for you. This chapter starts with a sense of where observables conceptually fit in the greater world of JavaScript tools. You’ll build your first project of the book: a stopwatch. A stopwatch may seem simple, but you’ll need to learn several key observable concepts to get it working. Once the stopwatch is up and running, you will prove the reusability of Rx by building a drag-and-drop example from the stopwatch code using the exact same pattern and operators. First things first, though, it’s time for Rx basics.

Using the Code Provided for This Section

The files you’ll edit in this section’s examples are located in the vanilla directory, organized by chapter (so this chapter’s examples are in vanilla/creatingObservables). Every example has (at least) three files: an HTML file, a JavaScript file for you to fill in, and another JavaScript file marked with the suffix -complete. The complete files contain the finished example and are there to help you out if you get stuck. To set up the server for this chapter’s code, make sure you’re in the vanilla directory and run npm install. When that’s complete, run npm start to get the Webpack dev server going. To get started, open your browser to http://localhost:8081.