Lightweight dependency injection in Elixir (without the tears)

By on in Development, Elixir

In our last Elixir blog post, “Functional Mocks with Mox in Elixir”, we discussed how testing across module boundaries could be made easier by creating a Behaviour for a collaborating module, then utilizing the wonderful framework Mox to substitute a lightweight mock module in tests.

This approach is well and good when you have very concrete module boundaries that are well-defined and coarse enough to warrant the ceremony of wiring up a behavior for a module boundary. But what if we aren’t necessarily interested in all the work in creating a mock, and we need something simpler and more lightweight?

Join us as we discuss some alternative ways to write lightweight tests across function or module boundaries.

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Comparing Dynamic Supervision Strategies in Elixir 1.5 and 1.6

By on in Development, Elixir

Classroom

Let’s say you’re managing complex process state in your Elixir application and you need a way to spin up and down new processes as your app runs. This requirement is known as dynamic supervision, the ability for a supervisor to add processes to its supervision tree at runtime.

This post will explain how to implement a process under dynamic supervision with Elixir 1.5, and discuss how Elixir 1.6’s new DynamicSupervisor is easier to configure and is more flexible.

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An Introduction to ADTs and Structural Pattern Matching in TypeScript

By on in Development

Preface

To quote Rúnar Bjarnason:

One of the great features of modern programming languages is structural pattern matching on algebraic data types. Once you’ve used this feature, you don’t ever want to program without it. You will find this in languages like Haskell and Scala.

I couldn’t agree more myself. That said, I spend most of my time writing programs with languages that don’t have first-class support for algebraic data types (ADTs). So what’s a programmer to do? Continue reading …


Taking Elm for a Test Drive

By on in Development, JavaScript

Elm emerged on the scene in early 2012 as a strongly-typed, functional language that compiles down to Javascript. With its architecture and type system, it claims to provide bulletproof guardrails to help developers build systems that are highly reliable, with “no runtime exceptions in practice”.

Elm prides itself on having a low barrier of entry – it can be introduced as a component into an existing web app, so long as your app can provide it a self-contained div. In fact, the creators of Elm strongly advocate taking an incremental approach to introducing Elm into your systems.

Lately, a few Carbon Fivers and I have been taking the language out for a spin and discovering what it means to write software systems in Elm. In this post, we’ll walk through what it looks like to take a small form widget written in vanilla jQuery and convert it to Elm, picking up language basics and learning to write apps the Elm way. We’ll also discuss the unique feature set that makes Elm apps so reliable.

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Using Host Instead of “replace: true” in Angular 4

By on in Development

Let’s say that you’re working on an Angular 4 app that displays some images. You want to add a directive you can apply to any image tag to make it look fancy when you mouse over it. You also want a component that will take up 100% of its parent container’s width and display an array of images in a flex row. Let’s call these FancyImageDirective and ImageRowComponent. Continue reading …


Always Squash and Rebase your Git Commits

By on in Development

Using git for version control allows for powerful collaboration in tech teams. Like any tool, if misused, it can also cause some serious headaches. After working with a wide variety of team sizes and dynamics, I’ve found that the squash and rebase workflow helps make the collaboration process more efficient and a hell of a lot less painful.

What is the squash rebase workflow?

It’s simple – before you merge a feature branch back into your main branch (often master or develop), your feature branch should be squashed down to a single buildable commit, and then rebased from the up-to-date main branch. Here’s a breakdown. Continue reading …