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JavaScript Katas: Sort and Star

July, 2020

Intro 🌐

Problem solving is an important skill, for your career and your life in general.

That’s why I take interesting katas of all levels, customize them and explain how to solve them.


Understanding the Exercise❗

First, we need to understand the exercise! If you don’t understand it, you can’t solve it!.

My personal method:

  1. Input: What do I put in?
  2. Output: What do I want to get out?

Today’s exercise

Source: Codewars

Write a function sortAndStar, that accepts one parameter: stringArray.

Given an array, e.g. ["We", "solve", "Katas"], sort it alphabetically (case-sensitive) and return the first string of the sorted array, with all characters separated by *** between each other, e.g. "K***a***t***a***s".


Input: an array of strings.

Output: a string.


Thinking about the Solution 💭

I think I understand the exercise (= what I put into the function and what I want to get out of it).

Now, I need the specific steps to get from input to output.

I try to do this in small baby steps:

  1. Sort the array (case-sensitive)
  2. Take the first array element
  3. Put *** between each char

Example:

  • Input: ["We", "solve", "Katas"]
  • Sort array: ["Katas", "We", "solve"] (case-sensitive)
  • Take first array element: "Katas"
  • Put *** between each char: "K***a***t***a***s"
  • Output: "K***a***t***a***s"

Implementation ⛑

function sortAndStar(stringArray) {
  const sorted = stringArray.sort(); // the default sort function works
  return sorted[0] // take first element
    .split("") // split string into chars
    .join("***"); // join chars with ***
}

Result

console.log(sortAndStar(["We", "solve", "Katas"]));
// "K***a***t***a***s" ✅

Playground ⚽

You can play around with the code here


Next Part ➡️

Great work!

We learned how to use sort, split and join.

I hope you can use your new learnings to solve problems more easily!

Next time, we’ll solve another interesting kata. Stay tuned!


If I should solve a specific kata, shoot me a message here.

If you want to read my latest stuff, get in touch with me!


Further Reading 📖


Questions ❔

  • How often do you do katas?
  • Which implementation do you like more? Why?
  • Any alternative solution?

miku86

Hi! I'm Michael 👋 I'm a Mentor & Educator & Senior Web Developer - I help you to reach your (career) goals.