Getting Started with Marble Testing

Todd Leininger Articles, Testing, Tutorial Leave a Comment

When working with RxJS observables, it can get a little tricky to unit test. Sometimes it can be hard to get insight into what is going on with the observable in the test. I’ve personally been frustrated numerous times by trying to test my observables with the subscribe and assert method. This is where marble testing can make testing observables easier.

The main advantage of using marble testing is the marble diagrams. With the diagrams, we have a visual representation of our observables and subscriptions so we can see the interactions between the two. Once the basics are understood, you should be able to get observable tests running in no time.

In this post, I will show you how to get started using Marble testing with an example. By the end, you should have enough information to get started on your journey testing observables. My examples are based on an Angular application using Jasmine, but these can also be applied to different testing frameworks for React and other applications.

JavaScript Optional Chaining – An Introduction

Lawrence Chabela Articles, CSS & HTML, Development Technologies & Tools, JavaScript 1 Comment

There is a new exciting feature coming to JavaScript in the not-so-far future. That feature is Optional Chaining. At this moment, Optional Chaining is in Stage 3 of the TC39 process, so it’s in late stages of the process and will be here soonish.

In general terms, Optional Chaining is an approach to simplify JavaScript expressions for accessing deeply nested values, array items, and methods when there is a possibility that a reference may be missing.

In this blog, we give an introduction to Optional Chaining in JavaScript. We discuss what problems Optional Chaining solves, the various ways you can use it, and relatable code examples.

Development: Microservices Analytics UI with React & Spring

Keyhole Software Java, JavaScript, Microservices, New Development, React, Technology & SaaS, Transportation & Logistics

A team of Keyhole Software Consultants built a customer-facing analytics dashboard for an international leader in automotive data and software services. This project was performed under an aggressive deadline and was completed both early and under budget.

The goal of the project was to both build the analytics dashboard and make all data accessible through a REST API. The development team was also tasked with building a custom solution for user authentication using JWTs to control access based on user subscriptions through an API Gateway.

Progressive Web Apps Tips and Tricks

Progressive Web App Tips and Tricks

John Boardman Articles, CSS & HTML, HTML5 4 Comments

PWA (Progressive Web App) is a powerful solution to multiple problems. Prior to PWA, there were some browser-specific implementations to some of the problems solved by PWA, but PWA is much more elegant while solving more problems at the same time.

In this post, we’ll cover the problems PWA was created to solve, some of the solutions PWA replaced, tools that make PWA development faster and more flexible, and tips to get the most out of PWA development.

Elm Language

Lou Mauget Articles, Development Technologies & Tools, JavaScript, Programming, Single-Page Application Leave a Comment

This blog is about my dalliance with Elm; a purely functional, statically typed language that has type inference. It compiles to JavaScript. Functional programming is compelling, but heretofore, I’d only woven cherry-picked techniques into large object-oriented projects. In FP parlance, I’m partially applied! The times, they are a-changin’.

In this article, I’ll:
– touch on the reasoning for giving a nod to functional languages and data immutability;
– move on to Elm; a blazing-fast, statically typed, purely functional browser-side language that compiles to JavaScript and follows the principles of functional reactive programming;
– survey background items and the Elm environment;
– show a simple type-and-click application, followed by a more realistic To-do application;
– end with my impressions from functional-programming semi-outsider point-of-view.