An Angular 2 chat app using Angular 2, RxJS, Angular CLI, Webpack, TypeScript, Services, Injectables, Karma, Forms, and tslint by the ng-book 2 team
This repo shows an example chat application using RxJS and Angular 2. The goal is to show how to use the Observables data architecture pattern within Angular 2. It also features:
- Angular CLI, which configures Webpack with TypeScript, Karma, and tslint
- Writing async components that work with RxJS
- How to write injectable services in Angular 2
- And much more
Try the live demo here
# clone the repo
git clone https://github.com/ng-book/angular2-rxjs-chat.git
# change into the repo directory
cd angular2-rxjs-chat
# install
npm install
# run
npm startThen visit http://localhost:4200 in your browser.
The app has three models:
Message- holds individual chat messagesThread- holds metadata for a group ofMessagesUser- holds data about an individual user
And there are three services, one for each model:
MessagesService- manages streams ofMessagesThreadsService- manages streams ofThreadsUserService- manages a stream of the currentUser
There are also three top-level components:
ChatNavBar- for the top navigation bar and unread messages countChatThreads- for our clickable list of threadsChatWindow- where we hold our current conversation
Each service publishes data as RxJS streams. The service clients subscribe to these streams to be notified of changes.
The MessagesService is the backbone of the application. All new messages are added to the newMessages stream and, more or less, all streams are derived from listening to newMessages. Even the Threads exposed by the ThreadsService are created by listening to the stream of Messages.
There are several other helpful streams that the services expose:
For example, the MessagesService exposes the messages stream which is a stream of the list of the all current messages. That is, messages emits an array for each record.
Similarly, the ThreadsService exposes a list of the chronologically-ordered threads in orderedThreads and so on.
Understanding how RxJS streams can be tricky, but this code is heavily commented. One strategy to grokking this code is to start at the components and see how they use the services. The other strategy is to get a copy of ng-book 2 where we explain each line in detail over ~60 pages.
This app implements a few simple chat bots. For instance:
- Echo bot
- Reversing bot
- Waiting bot
Step 1: Install Node.js from the Node Website.
We recommend Node version 4.1 or above. You can check your node version by running this:
$ node -v
vv4.1...Step 2: Install Dependencies
npm installnpm run goThen visit http://localhost:4200 in your browser.
You can run the unit tests with:
npm run testThere are two big changes we plan to make to this repo:
Currently the bots are all client-side and there are no HTTP requests involved in the chats.
We will move the chat bots to a server and integrate API requests into this project once the Angular 2 HTTP client development has settled down.
Because we're using observables, we can improve the performance of these components by using ON_PUSH change detection. Again, once Angular 2 development stabilizes, we'll be making this change.
There are lots of other little things that need cleaned up such as:
- More tests
- Cleaning up the vendor scripts / typings
- Simplifying the unread messages count
If you'd like to contribute, feel free to submit a pull request and we'll likely merge it in.
If you're having trouble getting this project running, feel free to open an issue, join us on Gitter, or email us!
This repo was written and is maintained by the ng-book 2 team. In the book we talk about each line of code in this app and explain why it's there and how it works.
This app is only one of several apps we have in the book. If you're looking to learn Angular 2, there's no faster way than by spending a few hours with ng-book 2.