RxJS

We are in the process of building a modern content platform to deliver our content through various channels. We decided to go with Microservices architecture as we wanted scale. Microservice architecture style is an approach to developing an application as a suite of small independently deployable services built around specific business capabilities. You can gain modularity, extensive parallelism and cost-effective scaling by deploying services across many distributed servers. Microservices modularity facilitates independent updates/deployments, and helps to avoid single point of failure, which can help prevent large-scale outages. We also decided to use Event Driven Architecture pattern which is a popular distributed asynchronous architecture pattern used to produce highly scalable applications. The event-driven architecture is made up of highly decoupled, single-purpose event processing components that asynchronously receive and process events.

To build our #Backend capabilities we decided to use the following: 1. #Microservices - Java with Spring Boot , Node.js with ExpressJS and Python with Flask 2. #Eventsourcingframework - Amazon Kinesis , Amazon Kinesis Firehose , Amazon SNS , Amazon SQS, AWS Lambda 3. #Data - Amazon RDS , Amazon DynamoDB , Amazon S3 , MongoDB Atlas

To build #Webapps we decided to use Angular 2 with RxJS

#Devops - GitHub , Travis CI , Terraform , Docker , Serverless

Material Design for Angular Angular 2 Node.js TypeScript Spring-Boot RxJS Microsoft SQL Server Hibernate Spring MVC

We built our customer facing portal application using Angular frontend backed by Spring boot.

One TypeScript / Angular 2 code health recommendation at Google is how to simplify dealing with RxJS Observables. Two common options in Angular are subscribing to an Observable inside of a Component's TypeScript code, versus using something like the AsyncPipe (foo | async) from the template html. We typically recommend the latter for most straightforward use cases (code without side effects, etc.)

I typically review a fair amount of Angular code at work. One thing I typically encourage is using plain Observables in an Angular Component, and using AsyncPipe (foo | async) from the template html to handle subscription, rather than directly subscribing to an observable in a component TS file.

Subscribing in components

Unless you know a subscription you're starting in a component is very finite (e.g. an HTTP request with no retry logic, etc), subscriptions you make in a Component must:

1. Be closed, stopped, or cancelled when exiting a component (e.g. when navigating away from a page),
2. Only be opened (subscribed) when a component is actually loaded/visible (i.e. in ngOnInit rather than in a constructor).

AsyncPipe can take care of that for you

Instead of manually implementing component lifecycle hooks, remembering to subscribe and unsubscribe to an Observable, AsyncPipe can do that for you.

I'm sharing a version of this recommendation with some best practices and code samples.

#Typescript #Angular #RXJS #Async #Frontend

Earlier this year, we started developing a new app to help our runners deliver groceries to our customers. We chose React Native over a native app or a PWA and are really happy with it. So far, we really like what we are seeing. Development speed is fast and the tooling is awesome. The “learn once, write anywhere”-promise is really fulfilled and when we ran our project for the first time on iOS after a few weeks of development, we were excited to see how well it worked and what it looked like.

Read our blog post to learn more about how we use React Native, TypeScript, Redux.js, RxJS, CodePush, styled-components, React Storybook, Jest, and Prettier to develop this app, as well as our thought of what else we will do with it at Picnic.