Clojure: flattening key paths

This article will cover how to flatten the nested key paths of a map in Clojure. Turning a nested map like {:a {:b {:c {:d 1} :e 2}}} into a flat map like {:a-b-c-d 1 :a-b-e 2}.

Clojure: sorting tuples

A tuple is a finite ordered sequence of elements. A common use of tuples in Clojure is for representing pairs of data that are related. For example a key and a value when mapping over a map (hashmap/dictionary). That being said tuples can be of any length, and are a common way of representing larger sets of related data in languages that don't use maps as prolifically as Clojure. This articles explores sorting tuples in Clojure.

Clojure: generating HTML and XML

HTML and XML are ubiquitous, whether it's the pages of a static site or configuration for a logger, being able to programmatically generate these files can be really powerful. This article will cover how to generate HTML and XML files in Clojure.

Clojure: using java.time with

Java 8 introduced java.time to replace the existing java representations of time java.util.Date, java.sql.Timestamp etc. There were many problems with this old implementation: it wasn't thread safe, it had a clunky API and no built in representation for timezones. java.time is the successor to the fantastic joda.time project which solves all these problems. So if java.time fixes everything then why this article? Well, java.sql.Timestamp still rears its ugly head at the database layer where it is still the default representation of time in the java.jdbc database drivers. In this article we will cover how to automate the conversion between java.sql.Timestamp and java.time so you never have to deal with java.sql.Timestamp again.

Clojure: connection pooling with hikari-cp

Connection pooling is a technique for improving app performance. A pool (cache) of reusable connections is maintained meaning when users connect to the database they can reuse an existing connection. When the user finishes using the connection it is placed back in the pool for other users to use. This reduces the overhead of connecting to the database by decreasing network traffic, limiting the cost of creating new connections, and reducing the load on the garbage collector. Effectively improving the responsiveness of your app for any task that requires connecting to the database.

Clojure: emoji in strings

Sometimes your problem domain requires the use of emoji. This article will cover how emoji are represented in Clojure strings.

Clojure: intro to tap> and accessing private vars

Clojure 1.10 introduced a new system called tap. From the release notes: tap is a shared, globally accessible system for distributing a series of informational or diagnostic values to a set of (presumably effectful) handler functions. It can be used as a better debug prn, or for facilities like logging etc.

Clojure: sorting a sequence based on another sequence

Sometimes web responses contain an unordered sequence of items along with a separate manifest that specifies the ordering. This article will cover how you can write a function to sort the list of items by the manifest order as well as using Clojure Spec to generate test data to verify its output.