At makandra, we've built a few gems over the years. Some of these are quite popular: spreewald (> 1M downloads), active_type (> 1M downloads), and geordi (> 200k downloads)

Developing a Ruby gem is different from developing Rails applications, w...

Sometimes you might want to limit the number of associated records in a has_many association, but cannot add a foreign key to the other model (using belongs_to).

There are [many](http://stackoverflow.com/questions/8153051/rails-how-to-limit-n...

Let's say we have posts with an attribute title that is mandatory.

Our example feature request is to tag these posts with a limited number of tags. The following chapters explain different approaches in Rails, how you can assign such a...

Note: Modern Rails has two build pipelines, the asset pipeline (or "Sprockets") and Webpacker. The principles below apply for both, but the examples shown are for Sprockets.

Every page in your application uses many assets, su...

Jasmine has long standing support for writing asynchronous specs. In days gone by we used the done callback to achieve this, but these days it is possible to write much more readable specs.

Async specs

As a first example, say we want to chec...

While it might seem trivial to implement an invoice that sums up items and shows net, gross and vat totals, it actually involves a lot of rules and caveats. It is very easy to create invoices where numbers don't add up and a few cents are missing....

This are the steps I needed to do to add esbuild to an application that used the vanilla rails asset pipeline with sprockets before.

Preparations

1. update Sprockets to version 4
2. add a .nvmrc with your preferred node version (and instal...

Every Rails response has a default ETag header. In theory this would enable caching for multiple requests to the same resource. Unfortunately the default ETags produced b...

When using git diff, you might encounter weird characters where umlauts (or any other UTF-8) characters should be. It looks like this:

R<C3><BC>ckg<C3><A4>ngig # should be "Rückgängig"

However, not Git is to blame [but the less comma...

When logging in Rails, you can use the log_tags configuration option to add extra information to each line, like :request_id or :subdomain. However, those ...