Today I was solving my first algorithm challenge at FreeCodeCamp and I managed to solve from MDN web docs . Here is the script: function reverseString(str) { var str = str.split('').reverse().join(''); return str; } reverseString("hello"); to preserve non-BMP codepoints mixed with unicode code points (emoji, etc). read here Link P.S: don't try to do this while your variables are declared as const it won't work :)