JavaScript Katas: Sort and Star

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.

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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?

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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".

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Input: an array of strings.

Output: a string.

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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

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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" ✅

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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" ✅

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Playground ⚽

You can play around with the code here

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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!

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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!

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Further Reading 📖

• sort
• split
• join

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Questions ❔

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

Comments

[pentacular]

Let's avoid destroying our inputs.
And let's decompose it into vaguely sensible operations.

const sorted = (array) => array.slice().sort();
const starred = (string) => string.split('').join('***');
const sortedAndStarred = (array) => starred(sorted(array)[0]);

[miku86]

Nice work,
I like it!

[Jon Randy 🎖️]

const sortAndStar = stringArray=>[...stringArray.sort()[0]].join('***')

[miku86]

Hey Jon,

thanks for your solution!

So instead of using split, we convert the string into a new array by spreading it.