jfmengels' blog

Jeroen Engels

Written by Jeroen Engels, author of elm-review. If you like what you read, you can follow me on Twitter or sponsor me.

Global and configuration errors

April 06, 2021

I just released version of the , and of the CLI. The release of the Elm package contains some missing features that could be considered…

You thought you had no dead code?

February 20, 2021

Today I’m releasing a big patch release (v1.1.5) for , ’s main package to detect and remove unused code from Elm code. I wrote previously…

Great compiler messages? Great test failure messages!

February 18, 2021

If you’ve written a little bit of Elm code, I hope you’ve tried out which allows you to write and run tests for your Elm code (if you never…

Safe dead code removal in a pure functional language

January 28, 2021

A few months ago, a colleague of mine wrote this on Slack: Thanks to elm-review I was able to remove ~7300 lines of code in the front end in…

Test-only values

December 22, 2020

Opaque types is a great technique in Elm. It prevents misuse of a custom type by restricting the possible operations you can apply to it…

1 year of elm-review. What lies ahead?

September 29, 2020

elm-review v1 was released on September 29th 2019. Today therefore marks the first anniversary of its release! 🥳🎉 Ambitions I have pretty…

Hacktoberfest 2020

September 29, 2020

Hacktoberfest will be starting in two days, and it’s a good opportunity to get started in open-source and help out the projects you like or…

2.3.0 - Just try it out

September 08, 2020

This is going to be another simultaneous release for both the CLI and the Elm package. Both bring what I think are very exciting features…

What has happened since elm-review v2?

August 26, 2020

I am in the final preparations for a new (and exciting) release of , and I noticed I didn’t communicate all the changes that happened since…

Single out elements using phantom types

May 04, 2020

Today, I will showcase a technique to single out elements from a type, through the medium of a puzzle (which you can try to solve or ignore…

Safe unsafe operations in Elm

April 27, 2020

In Elm, we often have modules around a data type which needs a validation when you initially create it. For instance, the package defines a…

Safe unsafe operations in Elm

April 27, 2020

In Elm, we often have modules around a data type which needs a validation when you initially create it. For instance, the package defines a…

elm-review v2!

April 08, 2020

Today I am very excited to release 2.0.0 and to share its new features! tl;dr: Here is the list of the introduced features: New review…

Announcing elm-review

September 29, 2019

I am happy to announce the release of and its CLI. What is elm-review? is a tool that analyzes your project’s Elm code, and reports…

The API of a water tap

January 02, 2019

Let’s say we wanted to represent a water tap. This tap will have two knobs, one to control cold water output and another one for warm water…