Double Char

Instructions:

Given a string, you have to return a string in which each character (case-sensitive) is repeated once.

Examples (Input -> Output):

• "String" -> "SSttrriinngg"
• "Hello World" -> "HHeelllloo WWoorrlldd"
• "1234!_ " -> "11223344!!__ "

Thoughts:

1. I transform the string to an array and split it into individual letters.
2. I use the map() method to replace each letter to a double letter and join the array to a string.

Solution:

function doubleChar(str) { const array = str .split("") .map((arr) => arr.replace(arr, arr + arr)) .join(""); return array; } 

This is a CodeWars Challenge of 8kyu Rank