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JavaScript Katas: Freudian Translator

August, 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

Today as small kata with a little bit of historical background about Sigmund Freud.

Write a function toFreud, that accepts one parameter: myString.

Given a string, e.g. "Sigmund Freud", return the string with every word replaced by the word "sex", e.g. "sex sex". An empty string or no argument should result in an empty string.


Input: a string.

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. Return an empty string if string is empty or no argument
  2. Loop over every word of the string
  3. Replace each word with "sex"
  4. Return a string of all new words

Example:

  • Input: "Sigmund Freud"
  • Return an empty string if string is empty or no argument: false
  • Iteration 1: “Sigmund” => replace it => "sex"
  • Iteration 2: “Freud” => replace it => "sex"
  • Return a string of all new words: "sex sex"
  • Output: "sex sex"

Implementation (functional) ⛑

function toFreud(myString) {
  return !myString
    ? "" // return an empty string if string is empty or no argument
    : myString
        .split(" ") // split string into words
        .map((word) => "sex") // replace each word with `"sex"`
        .join(" "); // put replaced words together
}

Result

console.log(toFreud("Sigmund Freud"));
// "sex sex" ✅

console.log(toFreud(""));
// ""  ✅

Implementation (regex) ⛑

function toFreudRegex(myString) {
  return !myString
    ? ""
    : myString.replace(/\S+/g, "sex"); // find all places that have "one or more non-white space", replace them with "sex"
}

The regex \S character class “matches a single character other than white space”. You can read about it here.

The regex + quantifier “matches the preceding item 1 or more times”. You can read about it here.

Result

console.log(toFreud("Sigmund Freud"));
// "sex sex" ✅

console.log(toFreud(""));
// ""  ✅

Playground ⚽

You can play around with the code here


Next Part ➡️

Great work!

We learned how to use split, map, join, replace and some regex.

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.