SKB – Scala implicit class


This article is part of the Scala knowledge bits Series.

Periodically, I will publish new exercises so you can slowly build up knowledge about Scala.

It is designed to be done in a very short amount of time and learn a little bit each day, just to create a routine.

This episode will teach you about Scala implicit class.

Hope you are going to enjoy it! It is designed for anyone to learn Scala from scratch and slowly learn, one Bit at a time.

After this Bit, I would love to hear your feedback in the comments down below.

Feel free to join the Discord server as well if you would like some help and support from the rest of our community.

What are we learning today?

Today we are going to learn about Scala implicit class !

Slowly getting into the more advanced features of Scala.

Starting with implicit class.

Time to try on the exercise on your own and scroll down for more information when you are done or if you are stuck.


Here is an exercise to complete today.

If I did my job well, you should be able to guess by yourself the solution based on what you previously learned and based on the clues.

But if you get stuck, scroll down to get more information.

The goal of the exercise is to replace the ??? by a piece of code so that the exercise compiles and that’s how you win! Good luck!

You can fill the exercise right in here:

Or, if it does not load, go on to Scastie (pDE2WSbNTtWv2MetlCCumw).

More information about Scala implicit class

In this exercise you will learn (or have learned, if you have already solved the puzzle) about Scala implicit class.

implicit class allows you to add methods to a type.

The syntax is like this:

implicit class NAME(value_name: TypeToOverride) {
  def methodToAdd: OutputType = ???

You might have noticed an other form:

implicit class NAME(val value_name: TypeToOverride) extends AnyVal {
  def methodToAdd: OutputType = ???

The second form will be more efficient, it will not create a new instance. The first form will create a new instance of the Type which can be inefficient if overused. Then, why not use the AnyVal form all the time ? There are a multitude of reasons, I could go over each and every ones of them, but this Stackoverflow answer explains it in a lot of details.

Feel free to go back to the exercise, modify the code to try out new things and get a better intuition for Scala implicit class.


I hope you have learned something new or had fun during this Scala Knowledge Bit.

Please ask questions or post feedback in the comments below.

Feel free to try on the next Scala Knowledege Bit.

If you are curious about the previous Scala knowledge Bits, go check it out! 🙂

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