JavaScript Kata #24: Opposite number

By YayoDrayber | Learn To Code With Me | 3 Sep 2022

If you missed the introductory post, it's here. For a list of previously solved katas, please refer to the bottom of this page.

If this is your first time seeing my post, please note - these katas are probably randomly assigned per user so please don't go into Codewars thinking we will have exactly the same user experience, I am just posting these in the order that I got them.

Kata #24

DESCRIPTION:

Very simple, given an integer or a floating-point number, find its opposite.

Examples:

1: -1
14: -14
-34: 34

Starting code:

function opposite(number) {
  //your code here
}

My attempt:

const opposite = number => number *= -1

Rank #1 in 'Best Practice':

function opposite(number) {
  return(-number);
}

Troll town in rank #2 with 1234 'Clever' votes by users ManuSensei and xdspacex:

function opposite(number) {
  /* Now this is the story all about how
      My life got flipped, turned upside down
      And I'd like to take a minute just sit right there
      I'll tell you how I became the prince of a town called Bel-air
      
      In west Philadelphia born and raised
      On the playground where I spent most of my days
      Chilling out, maxing, relaxing all cool
      And all shooting some b-ball outside of the school
      When a couple of guys, they were up to no good
      Started making trouble in my neighbourhood
      I got in one little fight and my mom got scared
      And said "You're moving with your auntie and uncle in Bel-air"
      
      I whistled for a cab and when it came near the
      License plate said "fresh" and had a dice in the mirror
      If anything I could say that this cab was rare
      But I thought nah, forget it, yo homes to Bel-air!
      
      I pulled up to a house about seven or eight
      And I yelled to the cabby "Yo, homes smell you later!"
      Looked at my kingdom I was finally there
      To sit on my throne as the prince of Bel-air */
  return -number;
}

Ranks #3, #4 and #5:

//Rank #3
const opposite = number => -number;

//Rank #4
function opposite(number) {
    return number * (-1);
}

//Rank #5
const opposite = n => -n;

The not-sure-if-trolling or just (maybe unnecessarily) meticulous approach at rank #6 by five users gbenavid, akremdakhli, Mehdi Cherif , user9429412, rabienajlaoui :

function opposite(number) {
  if (number === 0) {
    return 0;
  } else if (number.toString().includes('.') && number > 0) {
    return parseFloat("-" + number, 10);
  } else if (number > 0) {
    return parseInt("-" + number, 10);
  } else if (number < 0 && number.toString().includes('.')) {
    var didget = number.toString().split('-').pop();
    return parseFloat(didget);
  } else {
    var didgets = number.toString().split('-').pop();
    return parseInt(didgets);
  }
}

That's it for Kata #24, stay tuned for more katas to be solved!

Link to Kata #1: Square(n) Sum

Link to Kata #2: Convert a Number to a String

Link to Kata #3: DNA to RNA Conversion

Link to Kata #4: Remove First and Last Character

Link to Kata #5: MakeUpperCase

Link to Kata #6: Total amount of points

Link to Kata #7: A Needle in the Haystack

Link to Kata #8: Sum of positive

Link to Kata #9: Basic Mathematical Operations

Link to Kata #10: Beginner - Reduce but Grow

Link to Kata #11: Square Every Digit