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Onzin, onzin, allemaal onzin!

green and grey circuit board

I have a ridiculous amount of kernels

In previous blogposts I wrote about how I found a possible bug in the Linux kernel, or more precisely, in the kernel that Ubuntu derived from the mainline kernel.

To be able to install any kernel version 5.15.7 or higher, I also had to install libssl3.

The result is that I now have 37 kernels installed, taking up little over 2 GiB disk space:

$ (cd /boot ; ls -hgo initrd.img-* ; ls /boot/initrd.img-* | wc -l)
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.0-051300-generic
-rw-r--r-- 1 40M mrt  9 09:58 initrd.img-5.13.0-19-generic
-rw-r--r-- 1 40M mrt  9 09:58 initrd.img-5.13.0-20-generic
-rw-r--r-- 1 40M mrt  9 09:57 initrd.img-5.13.0-21-generic
-rw-r--r-- 1 44M mrt 30 17:46 initrd.img-5.13.0-22-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-23-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-25-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-27-generic
-rw-r--r-- 1 40M mrt  9 09:55 initrd.img-5.13.0-28-generic
-rw-r--r-- 1 40M mrt  9 09:55 initrd.img-5.13.0-30-generic
-rw-r--r-- 1 45M mrt  9 12:02 initrd.img-5.13.0-35-generic
-rw-r--r-- 1 45M mrt 24 23:17 initrd.img-5.13.0-37-generic
-rw-r--r-- 1 45M mrt 30 17:49 initrd.img-5.13.0-39-generic
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.1-051301-generic
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.19-051319-generic
-rw-r--r-- 1 37M mrt  9 09:53 initrd.img-5.13.19-ubuntu-5.13.0-22.22
-rw-r--r-- 1 37M mrt  9 09:53 initrd.img-5.13.19-ubuntu-5.13.0-22.22-0-g3ab15e228151
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-317-g398351230dab
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-356-g8ac4e2604dae
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-376-gfab6fb5e61e1
-rw-r--r-- 1 37M mrt  9 09:51 initrd.img-5.13.19-ubuntu-5.13.0-22.22-386-gce5ff9b36bc3
-rw-r--r-- 1 37M mrt  9 09:51 initrd.img-5.13.19-ubuntu-5.13.0-22.22-387-g0fc979747dec
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-388-g20210d51e24a
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-388-gab2802ea6621
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-391-ge24e59fa409c
-rw-r--r-- 1 37M mrt  9 09:49 initrd.img-5.13.19-ubuntu-5.13.0-22.22-396-gc3d35f3acc3a
-rw-r--r-- 1 37M mrt  9 09:49 initrd.img-5.13.19-ubuntu-5.13.0-22.22-475-g79b62d0bba89
-rw-r--r-- 1 37M mrt  9 09:48 initrd.img-5.13.19-ubuntu-5.13.0-23.23
-rw-r--r-- 1 40M mrt  9 09:48 initrd.img-5.14.0-051400-generic
-rw-r--r-- 1 40M mrt  9 10:31 initrd.img-5.14.21-051421-generic
-rw-r--r-- 1 44M mrt  9 12:39 initrd.img-5.15.0-051500-generic
-rw-r--r-- 1 46M mrt  9 12:16 initrd.img-5.15.0-22-generic
-rw-r--r-- 1 46M mrt 28 23:27 initrd.img-5.15.32-051532-generic
-rw-r--r-- 1 46M mrt 17 21:12 initrd.img-5.16.0-051600-generic
-rw-r--r-- 1 48M mrt 28 23:19 initrd.img-5.16.16-051616-generic
-rw-r--r-- 1 45M mrt 28 23:11 initrd.img-5.17.0-051700-generic
-rw-r--r-- 1 46M apr  8 17:02 initrd.img-5.17.2-051702-generic
37
  • Versions 5.xx.yy-zz-generic are installed with apt.
  • Versions 5.xx.yy-05xxyy-generic are installed with the Ubuntu Mainline Kernel Installer.
  • Versions 5.xx.yy-ubuntu-5.13.0-zz.zz-nnn-g<commithash> are compiled from source, where <commithash> is the commit of the kernel repository that I compiled.

The kernels in bold are the kernels where something unexpected happens with my USB devices:

  • Ubuntu kernels 5.13.23 and up – including 5.15 kernels of Ubuntu 22.04 LTS (Jammy Jellyfish).
  • Ubuntu compiled kernels, starting 387 commits after kernel 5.13.22.
  • Mainline kernels 5.15.xx.

When Ubuntu finally bases their kernel on mainline 5.16 or higher, then the USB bug will be solved.

blur bright business codes

Install libssl3 on Ubuntu versions before Jammy

Ubuntu mainline kernel packages 5.15.7 and later bump a dependency from libssl1.1 (>= 1.1.0) to libssl3 (>= 3.0.0~~alpha1).

However, package libssl3 is not available for Ubuntu 21.10 Impish Indri. It’s only available for Ubuntu 22.04 Jammy Jellyfish (which is still in beta as of time of writing) and later.

libssl3 further depends on libc6>=2.34 and debconf, but they are available in 21.10 repositories.

Here are a few different ways to resolve the dependency:

Option 1

Use apt pinning to install libssl3 from a Jammy repo, without pulling in everything else from Jammy.

This is more complicated, but it allows the libssl3 package to receive updates automatically.
Do all the following as root.

  • Create an apt config file to specify your system’s current release as the default release for installing packages, instead of simply the highest version number found. We are about to add a Jammy repo to apt, which will contain a lot of packages with higher version numbers, and we want apt to ignore them all.
$ echo 'APT::Default-Release "impish";' \
    | sudo tee /etc/apt/apt.conf.d/01ubuntu
  • Add the Jammy repository to the apt sources. If your system isn’t “impish”, change that below.
$ awk '($1$3$4=="debimpishmain"){$3="jammy" ;print}' /etc/apt/sources.list \
    | sudo tee /etc/apt/sources.list.d/jammy.list
  • Pin libssl3 to the jammy version in apt preferences. This overrides the Default-Release above, just for the libssl3 package.
$ sudo tee /etc/apt/preferences.d/libssl3 >/dev/null <<%%EOF
Package: libssl3
Pin: release n=jammy
Pin-Priority: 900
%%EOF
  • Install libssl3:
$ sudo apt update
$ sudo apt install libssl3

Later, when Jammy is officially released, delete all 3 files created above

$ sudo rm --force \
    /etc/apt/apt.conf.d/01ubuntu \
    /etc/apt/sources.list.d/jammy.list \
    /etc/apt/preferences.d/libssl3

Option 2

Download the libssl3 deb package for Jammy and install it manually with dpkg -i filename.deb.

This only works if there aren’t any additional dependencies, which you would also have to install, with a risk of breaking your system. Here Be Dragons…

green and black industrial machine

Printing multiple PDF files from console with lp

Recently I wanted to print some PDF files containing sheet music. The tedious way to do that, would be to open them one by one in Evince and press the print button. Surely there must be a more efficient way to do that?

$ ls -l --human-readable *.pdf
-r--r--r-- 1 amedee amedee 217K apr 15  2020 'Arthur original.pdf'
-r--r--r-- 1 amedee amedee 197K apr 13  2020 'Canal en octobre.pdf'
-r--r--r-- 1 amedee amedee  14K apr 13  2020  DenAndro.pdf
-r--r--r-- 1 amedee amedee  42K apr 14  2020 'Doedel you do.pdf'
-r--r--r-- 1 amedee amedee  57K apr 13  2020  Flatworld.pdf
-r--r--r-- 1 amedee amedee  35K apr 16  2020 'Jump at the sun.pdf'
-r--r--r-- 1 amedee amedee 444K jun 19  2016 'Kadril Van Mechelen.pdf'
-r--r--r-- 1 amedee amedee  15K apr 13  2020  La-gavre.pdf
-r--r--r-- 1 amedee amedee  47K apr 13  2020 'Le petit déjeuner.pdf'
-r--r--r-- 1 amedee amedee 109K apr 13  2020  LesChaminoux__2016_04_24.cached.pdf
-r--r--r-- 1 amedee amedee 368K apr 13  2020 'Mazurka It.pdf'
-r--r--r-- 1 amedee amedee 591K apr 13  2020 'Narrendans uit Mater.pdf'
-r--r--r-- 1 amedee amedee 454K apr 13  2020 'Neverending jig.pdf'
-r--r--r-- 1 amedee amedee 1,1M apr 14  2020 'Red scissors.pdf'
-r--r--r-- 1 amedee amedee  35K apr 13  2020  Scottish-à-VirmouxSOL.pdf
-r--r--r-- 1 amedee amedee  76K apr 14  2020 'Tarantella Napolitana meest gespeelde versie.pdf'
-r--r--r-- 1 amedee amedee 198K apr 15  2020 'Zot kieken!.pdf'

There are 2 console commands for printing: lp and lpr. One comes from grandpa System V, the other from grandpa BSD, and both are included in CUPS. The nice thing about these commands is that they know how to interpret PostScript and PDF files. So this is going to be easy: just cd into the directory with the PDF files and print them all:

$ lp *.pdf
lp: Error - No default destination.

Oops. A quick Google search of this error message tells me that I don’t have a default printer.

Configuring a default printer

First I use lpstat to find all current printers:

$ lpstat -p -d
printer HP_OfficeJet_Pro_9010_NETWORK is idle.  enabled since za 12 mrt 2022 00:00:28
printer HP_OfficeJet_Pro_9010_USB is idle.  enabled since za 12 mrt 2022 00:00:17
no system default destination

I have a HP OfficeJet Pro 9012e printer, which Ubuntu recognizes as a 9010 series. Close enough. It’s connected over network and USB. I’m setting the network connection as default with lpoptions:

$ lpoptions -d $(lpstat -p -d | head --lines=1 | cut --delimiter=' ' --fields=2)
copies=1 device-uri=hp:/net/HP_OfficeJet_Pro_9010_series?ip=192.168.1.9 finishings=3 job-cancel-after=10800 job-hold-until=no-hold job-priority=50 job-sheets=none,none marker-change-time=0 media=iso_a4_210x297mm number-up=1 output-bin=face-down print-color-mode=color printer-commands=none printer-info printer-is-accepting-jobs=true printer-is-shared=true printer-is-temporary=false printer-location printer-make-and-model='HP Officejet Pro 9010 Series, hpcups 3.22.2' printer-state=3 printer-state-change-time=1649175159 printer-state-reasons=none printer-type=4124 printer-uri-supported=ipp://localhost/printers/HP_OfficeJet_Pro_9010_NETWORK sides=one-sided

I can then use lpq to verify that the default printer is ready:

$ lpq
HP_OfficeJet_Pro_9010_NETWORK is ready
no entries

Printing multiple files from console

I found that if I naively do lp *.pdf, then only the last file will be printed. That’s unexpected, and I can’t be bothered to find out why. So I just use ls and feed that to a while-loop. It’s quick and dirty, and using find+xargs would probably be better if there are “special” characters, but that’s not the case here.

There’s one caveat: when the PDF files are printed one by one, then the first page will be at the bottom of the paper stack, so I need to print them in reverse order.

$ ls --reverse *.pdf | while read f; do lp "$f"; done

With that command I got 17 print jobs in the printer queue, one for each file.

Now that I know how to print from console, I’ll probably do that more often. The man page of lp describes many useful printing options, like printing double sided:

$ lp -o media=a4 -o sides=two-sided-long-edge filename
microphotography of orange and blue house miniature on brown snail s back

Moving!

A few months ago I wrote about my preferred region to work. Well, that’s no longer true. The co-housing project where I live (in Merelbeke, near Ghent) is going to end, and I need to move by the end of July 2022.

This also has an influence on my preferred place to work. I have decided to find a place to live not too far from work, wherever that may be (because I’m still on the #jobhunt). Ideally it would be inside the triangle Ghent-Antwerp-Brussels but I think I could even be convinced by the Leuven area.

Factors I’ll take into account:

  • Elevation and hydrology – with climate change, I don’t want to live somewhere with increased risk of flooding.
  • Proximity of essential shops and services.
  • Proximity of public transport with a good service.
  • Proximity of car sharing services like Cambio.
  • Not too far from something green (a park will do just fine) to go for a walk or a run.

I haven’t started looking yet, I’m not even sure if I want to do co-housing again, or live on my own. That’ll depend on the price, I guess. (Living alone? In this economy???) First I want to land on a job.

That makes sense—without knowing where I will be working, house hunting feels a bit like putting the cart before the horse. Still, I find myself browsing listings occasionally, more out of curiosity than anything else. It is interesting to see how prices and availability vary wildly, even within the triangle I mentioned. Some towns look charming on paper but lack the basics I need; others tick all the boxes but come with a rental price that makes my eyebrows do gymnastics.

In the meantime, I am mentally preparing for a lot of change. Leaving my current co-housing situation is bittersweet. On one hand, it has been a wonderful experience: shared dinners, spontaneous conversations, and a real sense of community. On the other hand, living with others also means compromise, and part of me wonders what it would be like to have a space entirely to myself. No shared fridges, no waiting for the bathroom, and the joy of decorating a place to my own taste.

That said, co-housing still appeals to me. If I stumble upon a like-minded group or an interesting project in a new city, I would definitely consider it. The key will be finding something that balances affordability, autonomy, and connection. I do not need a commune, but I also do not want to feel isolated.

I suppose this transition is about more than just logistics—it is also a moment to rethink what I want day-to-day life to look like. Am I willing to commute a bit longer for a greener environment? Would I trade square meters for access to culture and nightlife? Do I want to wake up to birdsong or the rumble of trams?

These are the questions swirling around my head as I polish up my CV, send out job applications, and daydream about future homes. It is a lot to juggle, but oddly enough, I feel optimistic. This is a chance to design a new chapter from scratch. A little daunting, sure. But also full of possibility.

mailboxes on metal fence

How I organize my message flow

Email

I use 2 email clients at the same time: Thunderbird and Gmail.

  • Thunderbird: runs on my local system, it’s very fast, it shows me all the metadata of an email in the way I want, the email list is not paged, I can use it for high volume actions on email. These happen on my local system, and then the IMAP protocol gradually syncs it to Gmail. I also find that Thunderbird’s email notifications integrate nicer in Ubuntu.
  • Gmail: can’t be beaten for search. It also groups mail conversations. And then there are labels!
How to turn on Conversation View in Gmail

Gmail has several tabs: Primary, Social, Promotions, Updates and Forums. Gmail is usually smart enough that it can classify most emails in the correct tab. If it doesn’t: drag the email to the correct tab, and Gmail will ask you if all future emails of that sender should go to the same tab. This system works well enough for me. My email routine is to first check the tabs Social, Promotions and Forums, and delete or unsubscribe from most emails that end up there. All emails about the go to Updates. I clean up the other emails in that tab (delete, unsubscribe, filter, archive) so that only the emails remain. Those I give a label – more about that later. Then I go to the Inbox. Any emails there (shouldn’t be many) are also taken care of: delete, unsubscribe, filter, archive or reply.

Enable Gmail tabs
Gmail tabs

Google has 3 Send options: regular Send, Schedule send (which I don’t use) and Send + Archive. The last one is probably my favorite button. When I reply to an email, it is in most cases a final action on that item, so after the email is sent, it’s dealt with, and I don’t need to see it in my Inbox any more. And if there is a reply on the email, then the entire conversation will just go to the Inbox again (unarchived).

Send + Archive

I love labels! At the level of an individual email, you can add several labels. The tabs are also labels, so if you add the label Inbox to an archived email, then it will be shown in the Inbox again. At the level of the entire mailbox, labels behave a bit like mail folders. You can even have labels within labels, in a directory structure. Contrary to traditional mail clients, where an email could only be in one mail folder, you can add as many labels as you want.
The labels are also shown as folders in an IMAP mail client like Thunderbird. If you move an email from one folder to another, then the corresponding label gets updated in Gmail.
The filters that I use in my are work/jobhunt, work/jobhunt/call_back, work/jobhunt/not_interesting, work/jobhunt/not_interesting/freelance, work/jobhunt/not_interesting/abroad, work/jobsites and work/coaching. The emails that end up with the abroad label, are source material for my blog post Working Abroad?

The label list on the left looks like a directory structure. It’s actually a mix of labels and traditional folders like Sent, Drafts, Spam, Trash,… Those are always visible at the top. Then there is a neat little trick for labels. If you have a lot of labels, like me, then Gmail will hide some of them behind a “More” button. You can influence which labels are always visible by selecting Show if unread on that label. This only applies to top-level labels. When there are no unread emails with that label or any of it’s sublabels, then the label will be hidden below the More button. As soon as there are unread mails with that label or any of it’s sublabels, then the label will be visible. Mark all mails as read, and the label is out of view. Again, less clutter, you only see it when you need it.

Show if unread

Filters, filters, filters. I think I have a gazillion filters. (208, actually – I exported them to XML so I could count them) Each time I have more than two emails that have something meaningful in common, I make a filter. Most of my filters have the setting ‘Skip Inbox’. They will remain unread in the label where I put them, and I’ll read them when it’s convenient for me. For example, emails that are automatically labelled takeaway aren’t important and don’t need to be in the Inbox, but when I want to order takeaway, I take a look in that folder to see if there are any promo codes.

Email templates. Write a draft email, click on the 3 dots bottom right, save draft as template. Now I can reuse the same text so that I don’t have to write for the umpteenth time that I don’t do freelance. I could send an autoreply with templates, but for now I’ll still do it manually.

LinkedIn

I can be short about that: it’s a mess. You can only access LinkedIn messages from the website, and if you have a lot of messages, then it behaves like a garbage pile. Some people also have an expectation that it’s some sort of instant messaging. For me it definitely isn’t. And just like with email: I archive LinkedIn chats as soon as I have replied.

I used to have an autoreply that told people to email me, and gave a link to my CV and my blog. What do you think, should I enable that again?

vibrant jester figure in dramatic lighting

Reduce unit tests boilerplate with Jest’s .each syntax

When writing unit tests, especially in JavaScript/TypeScript with Jest, you often run into a common problem: repetition.
Imagine testing a function with several input-output pairs. The tests can become bloated and harder to read.
This is where Jest’s .each syntax shines. It lets you write cleaner, data-driven tests with minimal duplication.

The Problem: Repetitive Test Cases

Take a simple sum function:

function sum(a, b) {
  return a + b;
}

Without .each, you might write your tests like this:

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

test('adds 2 + 3 to equal 5', () => {
  expect(sum(2, 3)).toBe(5);
});

test('adds -1 + -1 to equal -2', () => {
  expect(sum(-1, -1)).toBe(-2);
});

These tests work, but they are verbose. You repeat the same logic over and over with only the inputs and expected results changing.

The Solution: Jest’s .each Syntax

Jest’s .each allows you to define test cases as data and reuse the same test body.
Here is the same example using .each:

describe('sum', () => {
  test.each([
    [1, 2, 3],
    [2, 3, 5],
    [-1, -1, -2],
  ])('returns %i when %i + %i', (a, b, expected) => {
    expect(sum(a, b)).toBe(expected);
  });
});

This single block of code replaces three separate test cases.
Each array in the .each list corresponds to a test run, and Jest automatically substitutes the values.

Bonus: Named Arguments with Tagged Template Literals

You can also use named arguments for clarity:

test.each`
  a    | b    | expected
  ${1} | ${2} | ${3}
  ${2} | ${3} | ${5}
  ${-1}| ${-1}| ${-2}
`('returns $expected when $a + $b', ({ a, b, expected }) => {
  expect(sum(a, b)).toBe(expected);
});

This syntax is more readable, especially when dealing with longer or more descriptive variable names.
It reads like a mini table of test cases.

Why Use .each?

  • Less boilerplate: Define the test once and reuse it.
  • Better readability: Data-driven tests are easier to scan.
  • Easier maintenance: Add or remove cases without duplicating test logic.
  • Fewer mistakes: Repeating the same code invites copy-paste errors.

Use Case: Validating Multiple Inputs

Suppose you are testing a validation function like isEmail. You can define all test cases in one place:

test.each([
  ['user@example.com', true],
  ['not-an-email', false],
  ['hello@world.io', true],
  ['@missing.local', false],
])('validates %s as %s', (input, expected) => {
  expect(isEmail(input)).toBe(expected);
});

This approach scales better than writing individual test blocks for every email address.

Conclusion

Jest’s .each is a powerful way to reduce duplication in your test suite.
It helps you write cleaner, more maintainable, and more expressive tests.
Next time you find yourself writing nearly identical test cases, reach for .each—your future self will thank you.

My take on the Gilded Rose kata

The Gilded Rose Kata by Emily Bache is a staple in refactoring exercises. It offers a deceptively simple problem: refactor an existing codebase while preserving its behavior. I recently worked through the TypeScript version of the kata, and this post documents the transformation from a legacy mess into clean, testable code—with examples along the way.

But before diving into the code, I should mention: this was my very first encounter with TypeScript. I had never written a single line in the language before this exercise. That added an extra layer of learning—on top of refactoring legacy code, I was also picking up TypeScript’s type system, syntax, and tooling from scratch.

🧪 Development Workflow

Pre-Commit Hooks

pre-commit.com is a framework for managing and maintaining multi-language pre-commit hooks. It allows you to define a set of checks (such as code formatting, linting, or security scans) that automatically run before every commit, helping ensure code quality and consistency across a team. Hooks are easily configured in a .pre-commit-config.yaml file and can be reused from popular repositories or custom scripts. It integrates seamlessly with Git and supports many languages and tools out of the box.

I added eslint and gitlint:

- repo: https://github.com/pre-commit/mirrors-eslint
  hooks:
    - id: eslint

  - repo: https://github.com/jorisroovers/gitlint
    hooks:
      - id: gitlint

GitHub Actions

GitHub Actions was used to automate the testing workflow, ensuring that every push runs the full test suite. This provides immediate feedback when changes break functionality, which was especially important while refactoring the legacy Gilded Rose code. The setup installs dependencies with npm, runs tests with yarn, and ensures consistent results across different environments—helping maintain code quality and giving confidence to refactor freely while learning TypeScript.

name: Build

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        node-version: [12.x]

    steps:
      - uses: actions/checkout@v2
      - name: Node.js
        uses: actions/setup-node@v1
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm install -g yarn
        working-directory: ./TypeScript
      - name: yarn install, compile and test
        run: |
          yarn
          yarn compile
          yarn test
        working-directory: ./TypeScript

🔍 Starting Point: Legacy Logic

Originally, everything was handled in a massive updateQuality() function using nested if statements like this:

if (item.name !== 'Aged Brie' && item.name !== 'Backstage passes') {
    if (item.quality > 0) {
        item.quality--;
    }
} else {
    if (item.quality < 50) {
        item.quality++;
    }
}

The function mixed different concerns and was painful to extend.

🧪 Building Safety Nets

Golden master tests are a technique used to protect legacy code during refactoring by capturing the current behavior of the system and comparing it against future runs. In this project, I recorded the output of the original updateQuality() function across many item variations. As changes were made to clean up and restructure the logic, the tests ensured that the external behavior remained identical. This approach was especially useful when the codebase was poorly understood or untested, offering a reliable safety net while improving internal structure.

expect(goldenMasterOutput).toEqual(currentOutput);

🧹 Refactoring: Toward Structure and Simplicity

1. Extracting Logic

I moved logic to a separate method:

private doUpdateQuality(item: Item) {
    // clean, focused logic
}

This isolated the business rules from boilerplate iteration.

2. Replacing Conditionals with a switch

Using a switch statement instead of multiple if/else if blocks makes the code cleaner, more readable, and easier to maintain—especially when checking a single variable (like item.name) against several known values. It clearly separates each case, making it easier to scan and reason about the logic. In the Gilded Rose project, switching to switch also made it easier to later refactor into specialized handlers or classes for each item type, as each case represented a clear and distinct behavior to isolate.

switch (item.name) {
    case 'Aged Brie':
        this.updateBrie(item);
        break;
    case 'Sulfuras':
        break; // no-op
    case 'Backstage passes':
        this.updateBackstage(item);
        break;
    default:
        this.updateNormal(item);
}

This increased clarity and prepared the ground for polymorphism or factory patterns later.

🛠 Polishing the Code

Constants and Math Utilities

Instead of magic strings and numbers, I introduced constants:

const MAX_QUALITY = 50;
const MIN_QUALITY = 0;

I replaced verbose checks with:

item.quality = Math.min(MAX_QUALITY, item.quality + 1);

Factory Pattern

The factory pattern is a design pattern that creates objects without exposing the exact class or construction logic to the code that uses them. Instead of instantiating classes directly with new, a factory function or class decides which subclass to return based on input—like item names in the Gilded Rose kata. This makes it easy to add new behaviors (e.g., “Conjured” items) without changing existing logic, supporting the Open/Closed Principle and keeping the code modular and easier to test or extend.

switch (true) {
    case /^Conjured/.test(item.name):
        return new ConjuredItem(item);
    case item.name === 'Sulfuras':
        return new SulfurasItem(item);
    // ...
}

🌟 Feature Additions

With structure in place, adding Conjured Items was straightforward:

class ConjuredItem extends ItemUpdater {
    update() {
        this.decreaseQuality(2);
        this.decreaseSellIn();
    }
}

A corresponding test was added to confirm behavior.

🎯 Conclusion

The journey from legacy to clean architecture was iterative and rewarding. Key takeaways:

  • Set up CI and hooks early to enforce consistency.
  • Use golden master tests for safety.
  • Start small with extractions and switch statements.
  • Add structure gradually—factories, constants, classes.
  • With a clean base, adding features like “Conjured” is trivial.

All this while learning TypeScript for the first time!

You can explore the full codebase and history here:
📦 Gilded Rose Refactoring Kata — TypeScript branch

Curious to try it yourself, also in other languages?
Fork Emily Bache’s repo here: GildedRose-Refactoring-Kata on GitHub

Jag lär mig spela nyckelharpa

In 2016 I did something unexpected: I picked up a nyckelharpa for the very first time.

Jag hade aldrig spelat ett instrument “på riktigt” tidigare. Visst, jag spelade blockflöjt i skolan – men jag var usel på det och hatade varje minut. So when I started learning nyckelharpa, it was a fresh beginning, a clean slate.

Varför nyckelharpa?

One of the biggest reasons I got interested in the nyckelharpa is because I love to dance – especially balfolk, and even more so the Swedish polska. Det började alltså med dansen. Jag lyssnade på mycket polska, och snart märkte jag att många av mina favoritlåtar spelades på nyckelharpa. Before I knew it, I wanted to try playing them myself.

Vad är en nyckelharpa?

A nyckelharpa is a traditional Swedish keyed fiddle. It has strings that you play with a bow, and instead of pressing the strings directly, you use wooden keys that stop the string at the correct pitch. Det ger en väldigt speciell klang – varm, vibrerande och nästan magisk. Jag blev förälskad i ljudet direkt.

Mina första steg

Jag började ta lektioner på musikskolan i Schoten, Belgien, där min lärare är Ann Heynen. Sedan dess har jag deltagit i många helgkurser och workshops i Belgien, Tyskland, Nederländerna och Storbritannien.
(Jag har inte varit i Sverige för kurser – ännu! Men det finns på min önskelista.)

Det var där jag fick lära mig av några av de mest inspirerande spelmän och -kvinnor jag någonsin träffat:
Jule Bauer, Magnus Holmström, Emilia Amper, Marco Ambrosini, Didier François, Josefina Paulson, Vicki Swan, David Eriksson, Olena Yeremenko, Björn Kaidel, Olov Johansson, Eléonore Billy, Johannes Mayr, Johan Lång, Alban Faust, Koen Vanmeerbeek, Eveline d’Hanens – och säkert många fler fantastiska musiker jag glömmer just nu.

Under kurserna har jag också fått många nya bekanta – och till och med riktiga vänner – från hela Europa.
We share the same passion for music, dancing, and culture, and it is amazing how the nyckelharpa can bring people together across borders.

Från hyra till egen nyckelharpa

Like many beginners, I started by renting an instrument. Men i 2019 kände jag att det var dags att ta nästa steg, och jag beställde min egen nyckelharpa från Jean-Claude Condi, en lutier i Mirecourt, Frankrike – ett historiskt centrum för instrumentbyggare.

Tyvärr slog pandemin till strax efter, och det dröjde ända till augusti 2021 innan jag kunde åka till Mirecourt och äntligen hämta min nyckelharpa. It was worth the wait.

En resa i både musik och språk

Att lära mig spela nyckelharpa väckte också mitt intresse för svensk kultur. I kept hearing Swedish in the songs, and in 2020, I finally decided to start learning the language.
Jag började läsa svenska på kvällsskola under läsåret, och under loven fortsatte jag att öva med Duolingo. Sedan dess har jag försökt kombinera mina två passioner: språket och musiken.

Jag lyssnar ofta på svenska låtar, spelar visor och folkmelodier, och ibland försöker jag sjunga med. It is not only a way to practice, it is also incredibly rewarding.

Spela för dans

One of my goals is to be able to play well enough that others can dance to my music – just like I love dancing to other people’s tunes.
Det är inte lätt, för när jag har lärt mig en låt utantill, har jag redan glömt hur den förra gick… Men jag fortsätter öva. En dag, så!

Vad händer härnäst?

Mitt mål är att en dag spela tillsammans med andra på en riktig spelmansstämma i Sverige – och kanske äntligen ta en kurs på plats i Sverige också.
Men fram till dess fortsätter jag att öva, att lära mig, och att njuta av varje ton.

Jag lär mig spela nyckelharpa. Och jag lär mig svenska. Två passioner, ett hjärta. ❤️

🎶 Vill du också börja?

Är du nyfiken på nyckelharpa? Eller kanske du dansar balfolk och vill kunna spela själv?
Do not wait as long as I did — rent an instrument, find a workshop, or try your first tune today.
And if you are already playing: hör gärna av dig! Let us jam, dance, or just talk nyckelharpa.

a black cat playing with a rope

What are my preferred roles?

Definitely a halfling barbarian. Alignment: chaotic neutral.

Oh, you didn’t mean tabletop role playing but job roles? Riiiight…

I don’t think that this blog post will ever be complete, and it will always be evolving. But at this point, some of the things that I see myself doing:

Anything related to Continuous Delivery in software. From my perspective, that may include:

  • Test Automation – I’ve done this a lot, I liked it and wouldn’t mind doing more of it.
  • DevOps – I’m still not sure if DevOps must be a separate role, or if other roles can work better if they apply DevOps principles. That being said, I have done some devops-ish things, I liked it, and I would sure like to do more of it.
  • Software Development – There, I’ve put it in writing. I haven’t done this yet in a work context, but I like doing it and learning about it. And really – isn’t test automation also writing software?

Maybe you noticed that in none of these things I mention a specific technology. There may be tech&tools that I already have experience with, and you can read about that in my CV or on LinkedIn, but that is not what this blog post is about. I believe that technologies can (and should) always be learned, and it’s more of an attitude to work quality-driven.

Technical Storytelling or Technical Community Management
Storytelling can help simplify the complexities of new technologies. It’s a combination of technical skills, communication skills and empathy. It’s about supporting a community by creating helpful content, from sample code to tutorials, blog posts(*) and videos; speaking at conferences; and helping improve a product or technology by collecting feedback from the community. I recently read a blog post on this, and I can totally recognize myself there.

(*) Yes, the blog posts that I’m writing now, are also written with that kind of role in mind.

Also have a look at the roles that I am not interested in (but do get a lot of emails about).

people inside a bus wearing masks

What is my preferred region?

When recruiters contact me, I invariably get asked in what region I am willing to work. Well. It depends.
(scroll down for a map if you don’t want to read).

The thing is, I actually enjoy going from point A to point B. At the same time, if it is in much less than ideal situations (lots of traffic, or crowded public transportation), then I may get overstimulated, which leads to fatigue and lack of concentration. The least enjoyable commute was only 20km, by car, but it typically took me more than one hour. This was when a new bridge was constructed over the Scheldt in Temse.

The most pleasant work experiences I had, involved these commute patterns:

  • A 3km bicycle ride (about 10 minutes).
  • 30 km by car, with the first 15 minutes on almost empty rural roads, and then 25 minutes on a highway in the direction that had the least amount of traffic.
  • 5km, which I did on foot in 50 minutes (I was training for the Dodentocht at the time).
  • 40km, which I did with 5 minutes bicycle, 35 minutes train, 5 minutes walking. Ideal for listening to one or two episodes of a podcast. Doing the same distance by car would taken me about the same amount of time, in ideal conditions. And I can’t focus on traffic and listen to a podcast at the same time.
  • 6km, which was 20 minutes on a bicycle or 12 minutes by car. I preferred cycling, because I had separate bike lanes for about 80% of the way. 20 minutes was also an ideal amount of time to listen to one epidode of a podcast.

That looks like a lot of cycling, even though I don’t really consider myself to be an athletic type. It’s also eco-friendly, even though I don’t really consider myself to be an eco-warrior.

I’m not a petrol head, I don’t know anything about cars. 4 wheels and steering wheel, that’s about the limit of my knowledge. Currently I don’t even have a car, I make use of car sharing services like Cambio on the rare occasions that I actually need a car. At the same time, I do enjoy the experience of driving, especially long, smooth stretches. For example each year I go to a music course somewhere in the middle of Germany. That’s a 5 hour drive, not including stops. I absolutely love the change of scenery along the way. But but me in city traffic for an hour and I get too much input.

I have found a website where you can draw a map of the places you can reach within a certain time: TravelTime (the also have an API! ❤️).

This is a map I made with the following data:

  • Yellow: reachable by cycling in 30 minutes or less. That’s about all of the city center of Ghent.
  • Red: reachable by public transport in 1 hour or less. That doesn’t get me to Antwerp, Mechelen or Kortrijk, but Brussels and Bruges are just about reachable.
  • Blue: reachable by car in 45 minutes or less. That barely touches Antwerp. Brussels: the north, west and south edges. Kortrijk and Bruges are also within reach. Why the cutoff at 45 minutes? Well, I would need really, really good other motivations to consider Brussels. Some time ago I thought that 30 minutes would be my maximum, but it isn’t. I’d rather call it an optimum than a maximum.
TravelTime

Even with this map, I still have a personal bias. Most of my social life occurs somewhere in the triangle Ghent-Antwerp-Brussels. It becomes harder to do something after work when working in West-Flanders. It’s not a hard pass, just a preference.

I have more to tell on this topic, so I might update this blog post later.