Observables Workshop

This is a dojo on the Zen Observable library: https://github.com/zenparsing/zen-observable

It has been adapted from the exercises kindly set up by https://github.com/araqnid (many thanks!)

Introduction

Run npm install
To execute tests, run npm test
Work through each of the exercises, for each test:
- Unignore the test (by changing xit to it)
- Make the test pass

Exercises

Standalone usage

Create an observable to emit the rainbow colours, and subscribe to it to print them out
- Passing an object to subscription
- Passing just functions to subscription
Observable.of() emits a sequence of values
Observable.forEach() as an alternative

Timing and observables

Write an Observable to make a delay
Write an Observable to output values at a fixed rate

Using Observables instead of callbacks

Given a simple callback-based API (e.g. nanoajax), wrap it up as an Observable
The same with an API that takes onSuccess and onError callbacks

Composing Observables

Wrap an Observable in another Observable to transform its output
- Simple transforms are simple, subscription is container’s unsubscribe
Use the .map method
Use the .filter method
Write an Observable to emit the values of other Observables in turn
- Use the .concat method
Write an Observable to propagate values from an underlying Observable at a fixed rate (auto-refresh)
Zen-observable provides some combining functions: merge, combineLatest, zip
- Should have all the pieces (delay, concat) now to easily demonstrate what these do