Learn Karma, Ngrx and Ngrx-store

Very (very) quick and simple start to using [NgRx](https://ngrx.io/).

RxJS powered state management for Angular applications, inspired by Redux.

ngrx

NgRx Ultra Small Quick Start

As your Angular application grows, it becomes more difficult to manage application state.

NgRx can help with that!

In this course, we will learn how to convert an Angular application from using stateful services into using NgRx.

We will accomplish this by adding a new feature, including building a reducer and actions. We'll also touch on using selectors to query our state, managing collections with NgRx entity, async operations, and hiding implementation details with the facade pattern.

Angular is a development platform for creating applications using modern web standards. Angular includes a wealth of essential features such as mobile gestures, animations, filtering, routing, data binding, security, internationalization, and beautiful UI components. It's extremely modular, lightweight, and easy to learn.

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Reactive State Management in Angular with ngrx

***Note: RxJS imports have changed since the publication of this course. The concepts being taught on RxJS are still applicable.**

Angular has many built-in features for working closely with RxJS to help you build entirely reactive applications. This course will teach you how to use Angular with RxJS. We will learn how to use the ngrx/store library to manage state in a clean, reactive "Redux style."

This course assumes you've got a working knowledge of Angular and reactive programming with RxJS. If you don't, you might want to watch the following courses to get you up to speed! 
- [Get Started with Angular](https://egghead.io/courses/get-started-with-angular) 
- [Introduction to Reactive Programming with RxJS](
https://egghead.io/series/introduction-to-reactive-programming). 
- [Step by Step Async Programming with RxJS](https://egghead.io/series/step-by-step-async-javascript-with-rxjs) 
- [Getting Started With Redux](https://egghead.io/series/getting-started-with-redux), a course by Redux's, Dan Abramov.

We also have Intermediary Angular courses if you'd like to acquire more in-depth knowledge. 
- [Dependency Injection](https://egghead.io/courses/angular-2-dependency-injection-di-explained
- [Components, Directives](https://egghead.io/courses/building-angular-components)
- [Forms](https://egghead.io/courses/intro-to-angular-forms)
- [Router](https://egghead.io/courses/intro-to-angular-router)
- [Animating Web Apps](https://egghead.io/courses/animate-angular-web-applications)



Build Redux Style Applications with Angular, RxJS, and ngrx/store

Reducers are also often used for changing a single property inside of other reducers. This lesson shows how a type can enter the people reducer, but then the people reducer can use a different type to call the clock reducer and get a value back.

Use a Reducer to Change an Object's Property Inside an Array

This lesson summarizes everything the course has covered and how Angular 2, RxJS, and ngrx/store work together to achive a reactive application.

Review of Angular 2, RxJS, and Reducers from ngrx/store

The scan operator in RxJS is the main key to managing values and states in your stream. Scan behaves just as a reduce function would, but scan is able to collect values from streams over time. This lesson covers using startWith to set the initial accumulator value then using scan to update the value of the clock from the clicks and interval.

Manage State in RxJS with StartWith and Scan

While you have multiple streams flowing into your scan operator, you'll need to map each stream to the specific values you need to update your state the way that you want. This lesson covers using the map operator to determine what the click and interval should do when the state is updated.

Map Streams to Values to Affect State

Angular templates use a special Async pipe to be able to render out Observables. This lesson covers the syntax used to create an Observable in Angular and then to render it out in the template.

https://github.com/johnlindquist/rxjs-in-angular2/tree/11aa4c29a4536dad0ef26b78d8f7f503e4372f74/src

Render an Observable with the Async Pipe

ngrx/store is a library that simplifies common RxJS patterns for managing state and gives you an easy api to use it within your Angular application. This lesson shows how to convert a common startWith and scan stream into an ngrx Store and reducer.

Use ngrx/store and Reducers for Angular Application State

Angular allows you to pass values from inputs simply by referencing them in the template and passing them into your Subject.next() call. This lesson shows you how to make a number input and pass the value so you can configure how much you want the clock to change.

Pass Template Input Values to Reducers

The components inside of your container components can easily accept Observables. You simply define your custom @Input then use the Async pipe when you pass the Observable in. This lesson walks you through the process of passing an Observable into a Component.

Pass Observables into Components with Async Pipe

Reducers can easily be used inside one another to update related state. This lesson shows how you can use the clock reducer inside of the people reducer to create the time for each new person.

Use Two Reducers Together

RxJS allows you to combine streams in various ways. This lesson shows you how to take a click stream and combine it with a store stream to use a value from the store inside a reducer.

Use a Value from the Store in a Reducer

Karma is essentially a tool which spawns a web server that executes source code against test code for each of the browsers connected.

karma

There are several steps involved with setting up [`Karma`](http://karma-runner.github.io/) to work on your webpack project. In this first step we'll initialize our karma configuration and setup our `package.json` `scripts`.

Initialize a Webpack Project with Karma for Testing

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

chai

[Chai](https://npmjs.com/package/chai) assertions work great with the [Mocha](https://npmjs.com/package/mocha) testing framework. In this lesson we'll walk through out to install Chai and [karma-chai](https://npmjs.com/package/karma-chai) so you can use the `expect` assertions in your tests.

Use Chai assertions for tests in a Karma project

When writing tests run by Karma for an application that’s bundled with webpack, it’s easiest to integrate webpack and Karma directly together. In this lesson we’ll see how to utilize the [`karma-webpack`](https://npmjs.com/package/karma-webpack) plugin and reuse our existing webpack configuration to preprocess our test files with webpack.

Use Karma for Unit Testing with Webpack

Stores can accept as many reducers as you need. This lesson covers adding a second reducer that will be used to control an array of people.

Add a Second Reducer to the Store

While action types allow you tell your reducer what action it should take, the payload is the data that your reducer will use to update the state. This lesson shows you how to pass an action payload along with your action type to update the state.

Dispatch Action Payloads to Reducers

Instead of simply pushing numbers on a timer into the template, now we'll move on to pushing actual Dates. We'll still use the Async pipe, but we'll also add on the Date pipe with some formatting to display the Date just the way we want it.

Render an Observable Date with the Async and  Date Pipes

A reducer needs to know what you want it to do whenever it's called. You do this by passing along an action type then the reducer can switch based on the type to achieve the logic you need. This lesson covers dispatching action types to your reducer to update the state based on that type.

Dispatch Action Types to Reducers

Observable.merge allows you take two different source streams and use either one of them to make changes to the same state of your data. This lesson shows how you can use a stream of clicks and an interval stream and use either one to update the clock.

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